2D arrays of diamond shaped cells having multiple josephson junctions

Abstract

A two-dimensional SQIF array and methods for manufacture can include at least two bi-SQUIDs that share an inductance. The bi-SQUIDs can be combined to establish a diamond-shaped cell. A plurality of the diamond shaped cells can be packed tightly together so that each cell shares at least three cell junctions with adjacent cells to establish the SQIF array. Because of the close proximity of the cells, the effect that the mutual inductances each cell has on adjacent cells can be accounted for, as well as the SQIF array boundary conditions along the array edges. To do this, a matrix of differential equations can be solved to provide for the recommended inductance of each bi-SQUID in the SQIF array. Each bi-SQUID can be manufactured with the recommended inductance to result in a SQIF having an increased strength of anti-peak response, but without sacrificing the linearity of the response.

Claims

1. A two-dimensional Superconducting Quantum Interference Filter (SQIF) array comprising: at least three cells arranged in two dimensions; each of said cells having at least two bi-Superconducting Quantum Interference Devices (bi-SQUIDs); said at least two bi-SQUIDs being merged together so that said bi-SQUIDs share at least two bi-SQUID junctions and at least one inductance, wherein said at least one inductance is varied to maintain an over-all anti-peak response by adjusting a hole size of a ground plane under said inductance.

2. The SQIF array of claim 1 wherein said cells are diamond-shaped or hexagonal-shaped when viewed in top plan.

3. The SQIF array of claim 1 wherein each of said cells has at least four cell junctions, and further wherein each of said cells shares at least three cell junctions with an adjacent cell.

4. The SQIF array of claim 1 wherein each said bi-SQUID has a loop size, wherein said loop sizes are uniform, and wherein said bi-SQUIDs have non-uniform inductances, and further wherein said non-uniform inductances are modeled to maintain said overall anti-peak response for said SQIF array that is linear.

5. A method for establishing a two-dimensional Superconducting Quantum Interference Filter (SQIF) array, comprising the steps of: A) providing a plurality of bi-Superconducting Quantum Interference Devices (bi-SQUIDs); B) merging at least two bi-SQUIDs to establish a plurality of array cells; said step B) being accomplished so that said at least two bi-SQUIDs share at least two bi-SQUID junctions and at least one inductance, and so that said step B) establishes at least four cell junctions, wherein said at least one inductance is varied to maintain an overall anti-peak response by adjusting a hole size of a ground plane under said inductance; and, C) connecting said array cells in a two-dimensional manner so that each array cell shares at least three cell junctions with another of said array cells.

6. The method of claim 5, wherein said array cells are diamond shaped or hexagonal shaped when viewed in top plan.

7. The method of claim 5, wherein each said bi-SQUID has a loop size, wherein said loop sizes are uniform, and wherein said step B) is accomplished using bi-SQUIDs having non-uniform inductances, and further comprising the step of: D) modeling said non-uniform inductances to maintain said overall anti-peak response for said SQIF array that is linear.

8. The method of claim 7, wherein said non-uniform inductances have a distribution of at least 30 percent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The novel features of the present invention will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similarly-referenced characters refer to similarly-referenced parts, and in which:

(2) FIG. 1 is a schematic diagram of a direct current Superconductive Quantum Interference Devices (DC-SQUID) as known in the prior art;

(3) FIG. 2 is a schematic diagram of a prior art bi-SQUID;

(4) FIG. 3 is a graphical representation of the voltage response of the DC-SQUID and bi-SQUID of FIGS. 1 and 2, as a function of magnetic field strength;

(5) FIG. 4 is a schematic diagram of a single cell dual bi-SQUID of the 2D Array of the present invention according to several embodiments;

(6) FIG. 5 is a graphical representation of the voltage response of the single cell dual bi-SQUID of FIG. 4 as a function of magnetic field strength;

(7) FIG. 6 is a top plan view of the single cell dual bi-SQUID of FIG. 4;

(8) FIG. 7 is a schematic view of the 2D SQIF array of the present invention according to several embodiments, which illustrate a plurality of the cells of FIGS. 4 and 5;

(9) FIGS. 8a-8i are schematic views of the various boundary conditions for the 2D SQIF array of FIG. 7;

(10) FIG. 9 is a top plan view of a portion of the 2D SQIF array of FIG. 7;

(11) FIG. 10 is a graphical representation of the voltage response of the 2D SQIF array of FIG. 7 as a function of magnetic field strength;

(12) FIG. 11 is a graphical representation of graphical representation of the flux noise spectral density versus frequency at the mid-point of the positive slope of the anti-peak in FIG. 10;

(13) FIG. 12 is a graphical representation of energy sensitivity versus frequency at the mid-point of the positive slope of the anti-peak in FIG. 10;

(14) FIG. 13 is a graphical representation of noise temperature at the mid-point of the positive slope of the anti-peak in FIG. 10; and,

(15) FIG. 14 is a block diagram, which illustrates steps that can be taken to accomplish the methods of the present invention according to several embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(16) A. Prior Art.

(17) In brief overview, and referring initially to FIGS. 1 and 2, a DC SQUID 10 and DC bi-SQUID 20 are shown. FIG. 1 is a schematic diagram of a single DC SQUID 10. DC SQUID 10 can have two Josephson Junctions (JJ's) 12a, 12b arranged in parallel, connected with superconducting material, as represented by the schematic diagram in FIG. 1. A DC bi-SQUID 20, which is a SQUID with an additional Josephson junction 12c bisecting the superconducting loop, was introduced as an alternative to traditional SQUIDs. DC bi-SQUIDs have shown superior linearity in the average voltage response anti-peak feature. In FIG. 2, (i.sub.b, i.sub.1, i.sub.2, i.sub.3, i.sub.4, i.sub.5) can be the normalized currents through bi-SQUID 20, (.sub.1, .sub.2, .sub.3) can represent the phases across the Josephson junctions 12a-12c, /2 is the parameter related to the inductance values and x.sub.e (point 14) can represent the point in the equations where the external fields (not shown) are included.

(18) The equations for modeling the JJ's for the DC SQUID of FIG. 1 can be derived using Kirchhoff's current law, which is the principle of conservation of electric charge and implies that at any junction in an electrical circuit the sum of currents flowing into that node is equal to the sum of currents flowing out of that node, along with a resistively shunted junction (RSJ) model of the over-damped JJ. The JJ's can be assumed to be symmetric such that for the normalized critical currents i.sub.c1=i.sub.c2=1.0. The system of equations that models a single DC SQUID dynamics is:

(19) $\begin{array}{cc}{\stackrel{.}{}}_1=J-\frac{1}{}\left({}_1-{}_2-{}_e\right)-\sin {}_1{\stackrel{.}{}}_2=J+\frac{1}{}\left({}_1-{}_2-{}_e\right)-\sin {}_2,& \left(1\right)\end{array}$
where .sub.1 and .sub.2 are the phases across each of the Josephson junctions and the dots denote the time differentiation with normalized time

(20) $={}_{c}t=\frac{2{\mathrm{eI}}_0{R}_N}{}t.$
The parameter .sub.c in =2/(.sub.0)(I.sub.0)(R.sub.N). The parameter R.sub.N in is the normal state resistance of the Josephson junctions and I.sub.0 is the critical current of the Josephson junctions.

(21) $=2\frac{{\mathrm{LI}}_0}{{}_0}$
is the nonlinear parameter related to the SQUID inductance

(22) $L,J=\frac{I_b}{2I_0},$
where I.sub.b is bias current, and .sub.e=2ax.sub.e, where x.sub.e is the normalized external magnetic field and

(23) $a=.{}_0\frac{h}{2e}2.07{10}^{-15}$
tesla meter squared is the flux quantum, where h is Plank's constant and 2e is the charge on the Cooper pair.

(24) The phase equations for the single DC bi-SQUID schematic in FIG. 2 can be derived in a similar way to those of the single DC SQUID. In this case there is a third junction J.sub.3 that is related to the first and second junctions through the phases: .sub.1+.sub.3=.sub.2. Using this relationship, all the terms that include .sub.3 can be replaced with .sub.2.sub.1, thereby reducing the number of phase equations needed to model the system from three to two. The governing equations for a single bi-SQUID are

(25) $\begin{array}{cc}{\stackrel{.}{}}_1=\frac{i_b}{2}-\frac{1}{3}\left({}_1-{}_2-{}_e\right)+\frac{1}{3}{i}_{c3}\sin \left({}_2-{}_1\right)-\frac{2}{3}\sin {}_1-\frac{1}{3}\sin {}_2{\stackrel{.}{}}_2=\frac{i_b}{2}+\frac{1}{3}\left({}_1-{}_2-{}_e\right)-\frac{1}{3}{i}_{c3}\sin \left({}_2-{}_1\right)-\frac{1}{3}\sin {}_1-\frac{2}{3}\sin {}_2,& \left(2\right)\end{array}$
where

(26) $i_{c3}=\frac{I_{c3}}{I_0}$
is the normalized critical current on the third junction and all other parameters are defined as the single DC SQUID.

(27) The voltage response of both the single DC SQUID 10 of FIG. 1 and the DC bi-SQUID 20 of FIG. 2 can be simulated by integrating the systems of equations that model the system dynamics, Eq (1) and Eq (2) respectively. After the phases .sub.1 and .sub.2 have been determined the derivatives {dot over ()}.sub.1 and {dot over ()}.sub.2 are evaluated and the time-dependent voltage

(28) $V\left(t\right)=\frac{{\stackrel{.}{}}_1+{\stackrel{.}{}}_2}{2}$
is calculated. The average voltage, <V>, of a SQUID (or bi-SQUID) at a point in x.sub.e is the mean value of the voltage over time. FIG. 3 illustrates the results of this process. FIG. 3 is an average voltage response of a single DC SQUID compared with that of a single DC bi-SQUID. The average voltage response of the bi-SQUID (line 32), with the proper selection of parameters, has a more linear average voltage response than the conventional DC SQUIDs (line 34 in FIG. 3) . The simulations were performed with J=1.0, =1.0 and i.sub.c3=1.0. The higher linearity of the average voltage response of the bi-SQUID can increase the overall utility of the device that incorporates the bi-SQUID as a linear amplifier, provided the bi-SQUIDs are incorporated to optimize the overal linearity of the device.

(29) The structure and cooperation of structure of the SQUID and bi-SQUID, and the design and performance of one-dimensional SQIF's using such components are discused in more detail in the aforementioned '994 application, which has been incorporated in its entirety into this specification.

(30) B. Dual Bi-SQUID Cell.

(31) Referring now to FIG. 4, FIG. 4 depicts a circuit of a dual bi-SQUID cell structure 40 of the present invention according to several embodiments. As shown in FIG. 4, cell 40 can further include at least two bi-SQUIDs 20a, 20b (indicated by the dotted lines in FIG. 4), which can be merged so that the bi-SQUIDs share at least one two bi-SQUID junctions 44a, 44b and at least one inductance 46. With this configuration, cell 40 can present a diamond shaped appearance when viewed in top plan. It should be appreciated, however, that other geometric views (such as hexangonal, for example) are possible, provided the equations discussed below are modified and derived using Kirchoff's law to account for the conservation of currents in such alternative embodiments.

(32) In FIG. 4, i.sub.b can be taken to represent an input base current into cell 40, (i.sub.1, . . . , i.sub.11) can represent the normalized currents through the various bi-SQUID junctions 44, and (.sub.1 . . . .sub.6) can represent the phases across the JJ's 42 in cell 40 through bi-SQUIDs 20, (L.sub.1, L.sub.2a, . . . , L.sub.6a, L.sub.2b, . . . , L.sub.6b) represent the parameters related to the inductances and x.sub.e (points 48a, 48b) can represent the points in the equations where the external fields are included. Using these representations, six governing equations are needed to simulate the average voltage response for this device, which contains 12 currents, 6 Josephson junctions and 9 inductors.

(33) Kirchhoff's current law results in the following relations for the currents and phases in the diamond-shaped dual bi-SQUID

(34) $\begin{array}{cc}\begin{array}{cc}{i}_b=i_1+i_2& i_1=i_3+i_8\\ i_2+i_3=i_9& i_8=i_7+i_{10}\\ i_9+i_7=i_{11}& i_{10}+i_6=i_4\\ i_{11}=i_6+i_5& i_4+i_5=i_b\\ i_1=\sin {}_1+{\stackrel{.}{}}_1& i_2=\sin {}_2+{\stackrel{.}{}}_2\\ i_4=\sin {}_4+{\stackrel{.}{}}_4& i_5=\sin {}_5+{\stackrel{.}{}}_5\\ i_3=i_{c3}\sin {}_3+{\stackrel{.}{}}_3& i_6=i_{c6}\sin {}_6+{\stackrel{.}{}}_6,\end{array}& \left(3\right)\end{array}$
where i.sub.c3=I.sub.c3/I.sub.0 is the normalized critical current of the third junction, i.sub.c6=I.sub.c6/I.sub.0 is the normalized critical current of the sixth junction, I.sub.c1=I.sub.c2=I.sub.c4=I.sub.c5=I.sub.0, and .sub.i are the phases across of the Josephson junctions for i=1, . . . ,6. The dots on the equations in this specficiation denote time differentiation with respect to normalized time =.sub.ct, where .sub.c and t remain defined as above. The resistively-shunted junction (RSJ) model provides a current-phase relation around the top half of the diamond of dual bi-SQUID cell 40 (bi-SQUID 20a)
.sub.1+L.sub.1i.sub.7+L.sub.2ai.sub.8=2x.sub.ea.sub.1+.sub.2+L.sub.2bi.sub.9,
where .sub.e=2a.sub.1x.sub.e, where x.sub.e is the normalized external magnetic flux and a.sub.1=L.sub.1+L.sub.2a+L.sub.2b. Combining i.sub.7=i.sub.8i.sub.10 and i.sub.7=i.sub.11i.sub.9 such that

(35) 0$i_7=\frac{i_8-i_{10}}{2}+\frac{i_{11}-i_9}{2},$
and then substituting the current relations for i.sub.7, i.sub.10, i.sub.9, and i.sub.8 yields

(36) $\begin{array}{cc}\left(\frac{L_1}{2}+L_{2a}\right)i_1-\frac{L_1}{2}{i}_4+\frac{L_1}{2}{i}_5+L_1{i}_6={}_2-{}_1+\left(\frac{L_1}{2}+L_{2b}\right)i_2+2x_e{a}_1+\left(L_1+L_{2a}+L_{2b}\right)i_3.& \left(4\right)\end{array}$

(37) In order to get the first of the six equations that is needed to describe the dynamics of the diamond shape, the bias current relation i.sub.2=i.sub.bi.sub.1 and Josephson junction relations from Eq. (3) are substituted into Eq. (4) to become

(38) $\begin{array}{cc}{L}_{12}\left({\stackrel{.}{}}_1-{\stackrel{.}{}}_3\right)+\frac{L_1}{2}\left(2{\stackrel{.}{}}_6+{\stackrel{.}{}}_5-{\stackrel{.}{}}_4\right)=\left(\frac{L_1}{2}+L_{2b}\right)i_b+{}_2-{}_1+2x_e{a}_1+L_{12}\left(i_{c3}\sin {}_3-\sin {}_1\right)+\frac{L_1}{2}\left(\sin {}_4-\sin {}_5-2i_{c6}\sin {}_6\right),& \left(5\right)\end{array}$
where L.sub.12=L.sub.1+L.sub.2a+L.sub.2b.

(39) To solve for the second of the six equations that governs the dynamics of the single diamond the current relations for the bias current i.sub.1=i.sub.bi.sub.2 and Josephson junctions from Eq. (3) are substituted into Eq. (4) to give

(40) $\begin{array}{cc}\frac{L_1}{2}\left(2{\stackrel{.}{}}_6+{\stackrel{.}{}}_5-{\stackrel{.}{}}_4\right)-L_{12}\left({\stackrel{.}{}}_2+{\stackrel{.}{}}_3\right)=-\left(\frac{L_1}{2}+L_{2a}\right)i_b+{}_2-{}_1+2x_e{a}_1+L_{12}\left(i_{c3}\sin {}_3+\sin {}_2\right)+\frac{L_1}{2}\left(\sin {}_4-\sin {}_5-2i_{c6}\sin {}_6\right),& \left(6\right)\end{array}$
where L.sub.12=L.sub.1+L.sub.2a+L.sub.2b.

(41) The RSJ model also provides a current-phase relation around the upper loop in the single diamond according to the equation .sub.1+.sub.3+L.sub.3i.sub.3=.sub.2, where L.sub.3=L.sub.3a+L.sub.3b. Substituting the Josephson junction relations from Eq. (3) and reorganizing yields the third of the six equations for the dynamics of the single diamond.
L.sub.3{dot over ()}.sub.3=.sub.2.sub.1.sub.3L.sub.3i.sub.c3 sin .sub.3.(7)

(42) A current-phase relation around the bottom half (bi-SQUID 20b) of the single diamond cell 40 can be determined to be .sub.4+L.sub.5ai.sub.10=2x.sub.ea.sub.2+.sub.5+L.sub.5bi.sub.11+L.sub.1i.sub.7, where .sub.e=2a.sub.2x.sub.e and a.sub.2=L.sub.1+L.sub.5a+L.sub.5b. Substituting the current relations

(43) $i_7=\frac{i_8-i_{10}}{2}+\frac{i_{11}-i_9}{2},$
i.sub.10=i.sub.4i.sub.6, i.sub.11=i.sub.5+i.sub.6, i.sub.9=i.sub.2+i.sub.3 and i.sub.8=i.sub.1i.sub.3 from Eq. (3) and then reorganizing gives

(44) $\begin{array}{cc}\left(L_{5a}+\frac{L_1}{2}\right)i_4-\left(L_1+L_{5a}+L_{5b}\right)i_6={}_5-{}_4+2x_e{a}_2+\left(L_{5b}+\frac{L_1}{2}\right)i_5+\frac{L_1}{2}{i}_1-\frac{L_1}{2}{i}_2-L_1{i}_3.& \left(8\right)\end{array}$
Substituting the current relation for the bias current i.sub.5=i.sub.bi.sub.4 from Eq. (3) into Eq. (8) and then substituting the Josephson junction relations from Eq. (3) and reorganizing leads to the fourth governing equation

(45) $\begin{array}{cc}{L}_{15}\left({\stackrel{.}{}}_4-{\stackrel{.}{}}_6\right)+\frac{L_1}{2}\left(2{\stackrel{.}{}}_3+{\stackrel{.}{}}_2-{\stackrel{.}{}}_1\right)=\left(L_{5b}+\frac{L_1}{2}\right)i_b+{}_5-{}_4+2x_e{a}_2+L_{15}\left(i_{c6}\sin {}_6-\sin {}_4\right)+\frac{L_1}{2}\left(\sin {}_1-\sin {}_2-2i_{c3}\sin {}_3\right),& \left(9\right)\end{array}$
where L.sub.15=L.sub.1+L.sub.5a+L.sub.5b.

(46) To solve for the fifth of the six equations for the dynamics of the single diamond shape the current relations for the bias current i.sub.4=i.sub.bi.sub.5 and Josephson junctions from Eq. (3) is substituted into Eq. (8) to become

(47) $\begin{array}{cc}\frac{L_1}{2}\left(2{\stackrel{.}{}}_3+{\stackrel{.}{}}_2-{\stackrel{.}{}}_1\right)-L_{15}\left({\stackrel{.}{}}_5+{\stackrel{.}{}}_6\right)=-\left(L_{5b}+\frac{L_1}{2}\right)i_b+{}_5-{}_4+2x_e{a}_2+L_{15}\left(i_{c6}\sin {}_6+\sin {}_5\right)+\frac{L_1}{2}\left(\sin {}_1-\sin {}_2-2i_{c3}\sin {}_3\right),& \left(10\right)\end{array}$
where L.sub.15=L.sub.1+L.sub.5a+L.sub.5b.

(48) For the sixth governing equations a current-phase relation can be found for the lower loop in the diamond
.sub.4+.sub.6+L.sub.6i.sub.6=.sub.5,
where L.sub.6=L.sub.6a+L.sub.6b. Substituting the Josephson junction relations from Eq. (3) into the relation and reorganizing yields
L.sub.6{dot over ()}.sub.6=.sub.5.sub.4.sub.6L.sub.6i.sub.c3 sin .sub.3.(11)

(49) The equations from Eq. (5)-(7) and Eq. (9)-(11) can be combined to obtain the full system of equations that governs the phase dynamics of the diamond-shaped bi-SQUID:

(50) $\begin{array}{cc}{L}_{12}\left({\stackrel{.}{}}_1-{\stackrel{.}{}}_3\right)+\frac{L_1}{2}\left(2{\stackrel{.}{}}_6+{\stackrel{.}{}}_5-{\stackrel{.}{}}_4\right)=\left(\frac{L_1}{2}+L_{2b}\right)i_b+{}_2-{}_1+2x_e{a}_1+L_{12}\left(i_{c3}\sin {}_3-\sin {}_1\right)+\frac{L_1}{2}\left(\sin {}_4-\sin {}_5-2i_{c6}\sin {}_6\right);\frac{L_1}{2}\left(2{\stackrel{.}{}}_6+{\stackrel{.}{}}_5-{\stackrel{.}{}}_4\right)-L_{12}\left({\stackrel{.}{}}_2+{\stackrel{.}{}}_3\right)=-\left(\frac{L_1}{2}+L_{2a}\right)i_b+{}_2-{}_1+2x_e{a}_1+L_{12}\left(i_{c3}\sin {}_3+\sin {}_2\right)+\frac{L_1}{2}\left(\sin {}_4-\sin {}_5-2i_{c6}\sin {}_6\right);L_3{\stackrel{.}{}}_3={}_2-{}_1-{}_3-L_3{i}_{c3}\sin {}_3;L_{15}\left({\stackrel{.}{}}_4-{\stackrel{.}{}}_6\right)+\frac{L_1}{2}\left(2{\stackrel{.}{}}_3+{\stackrel{.}{}}_2-{\stackrel{.}{}}_1\right)=\left(L_{5b}+\frac{L_1}{2}\right)i_b+{}_5-{}_4+2x_e{a}_2+L_{15}\left(i_{c6}\sin {}_6-\sin {}_4\right)+\frac{L_1}{2}\left(\sin {}_1-\sin {}_2-2i_{c3}\sin {}_3\right);\frac{L_1}{2}\left(2{\stackrel{.}{}}_3+{\stackrel{.}{}}_2-{\stackrel{.}{}}_1\right)-L_{15}\left({\stackrel{.}{}}_5+{\stackrel{.}{}}_6\right)=-\left(L_{5b}+\frac{L_1}{2}\right)i_b+{}_5-{}_4+2x_e{a}_2+L_{15}\left(i_{c6}\sin {}_6+\sin {}_5\right)+\frac{L_1}{2}\left(\sin {}_1-\sin {}_2-2i_{c3}\sin {}_3\right);\mathrm{and},L_6{\stackrel{.}{}}_6={}_5-{}_4-{}_6-L_6{i}_{c3}\sin {}_3,& \left(12\right)\end{array}$
where L.sub.12=L.sub.1+L.sub.2a+L.sub.2b, L.sub.3=L.sub.3a+L.sub.3b, L.sub.15=L.sub.1+L.sub.5a+L.sub.5b, L.sub.6=L.sub.6a+L.sub.6b and .sub.i are the phases on each of the Josephson junctions, i=1, . . . ,6. The normalized critical current on the third junction is

(51) $i_{c3}=\frac{I_{c3}}{I_0},$
the normalized critical current of the sixth junction is

(52) 0$i_{c6}=\frac{I_{c6}}{I_0},$
I.sub.c1=I.sub.c2=I.sub.c4=I.sub.c5=I.sub.0, x.sub.e is the normalized external magnetic flux, a.sub.1=L.sub.1+L.sub.2a+L.sub.2b and a.sub.2=L.sub.1+L.sub.5a+L.sub.5b.

(53) Once the equations above are solved for inductances, values can be substituted there for the inductance and the average voltage response for the diamond shaped bi-SQUID cell 40 of the present invention according to several embodiments is shown in FIG. 5. The response can be plottted for J=1.001, L.sub.1=0.54, L.sub.2a=L.sub.2b=L.sub.5a=L.sub.5b=0.24, L.sub.3a=L.sub.3b=L.sub.6a=L.sub.6b=0.3, and i.sub.c3=0.5 These values are all normalized values, without units. As shown in FIG. 5, this average voltage response retains its linearity, with proper choice of parameters, such as varying the inductances instead of the loop sizes the triangle-shaped bi-SQUIDs 20 in the cell. The actual size of the triangle could also be varied.

(54) Referring now to FIG. 6, FIG. 6 is a microphotograph of the single diamond bi-SQUID of FIG. 4. FIG. 6 shows the implementation of the diamond-shaped dual bi-SQUID cell once fabricated. One such fabrication method that can be used is the HYPRES Nb fabrication process, as described in Niobium (Nb) process design rule, revision #24, Jan. 11, 2008, 11, available at http://www.hypres.com. R.sub.shunt is the shunting resistance and V.sub.c is the critical voltage across each of the JJ's. For the fabrication shown in FIG. 6, J1=J2=J3=0.25 mA, R.sub.shunt=2.4 , V.sub.c=I.sub.cR.sub.sh=600 V.

(55) The cell 40 shown in FIG. 6 can be manufactured using all four Nb layers: a ground plane layer, two layers for junctions and inductors, and a top layer to implement a flux bias line 50 overlaying the bi-SQUID cells. The ground plane was used only under Nb layers forming bi-SQUID inductors and junctions in order to maintain their low specific inductance. However, ground plane can be partially removed from under inductor 46 to increase its inductance value, if desired. The ground plane can also be removed from the central area of the bi-SQUID loops (areas 52 in FIG. 6) to allow an external magnetic field to thread through the cell.

(56) C. Implementation of 2D Diamond bi-SQUID SQIF Arrays.

(57) 1. Construction of 2D SQIF Array.

(58) To construct the 2D SQIF array of the present invention according to several embodiments, and referring now to FIGS. 7-9, building blocks of dual bi-SQUID cells 40 like those shown in FIG. 6 can be used. The repeating pattern in the 2D array that is illustrated in FIGS. 7-9 can be a series of cells 40 having a diamond shape created by two bi-SQUIDs 20a, 20b, which can have the structure as recited above for cell 40 (See FIG. 4). An example of such as array is shown electrically and in top plan in FIG. 7. The phase equations that model the 2D diamond arrays can be derived in a similar way as the single diamond structure of bi-SQUIDs. But the above analysis in the previous section and Equations (5)-(7) and (9)-(11) only models the response for one cell 40. To model the effects for the SQIF array as a whole, the analysis can now be extended to the full 2D diamond array. But because of the tightly packed arrangement of diamond-shaped cells 40, each bi-SQUID shares its JJs and inductances with neighboring bi-SQUIDs. Stated differently, each bi-SQUID cell 40 affect adjacent bi-SQUID cells 40 as well of the bi-SQUIDs of other cells 40 in the array 70. Therefore to model the entire array, Kirchoff's law can be used to sum current thorugh each and every junciton for a network of cells 40 that share inductances, instead of a single cell. Also, the effects that each cell 40 has on every other cell in the 2D array, and the effects that occur at boundary conditions can be accounted for (again, using Kirchoff's law) in the methods of the present invention.

(59) At the corners of the 2D SQIF array 70, each dual bi-SQUID cell 40 has a contact to three neighboring cells at cell junctions 80. FIGS. 8b, 8d, 8g and 8i illustrate this boundary condition at the respective upper left, upper right, lower left and lower right corners of the 2D SQIF array. FIGS. 8e and 8f illustrate the boundary conditions on the respective left side and right side of the 2D SQIF array. FIGS. 8c and 8h illustrate the respective top and bottom conditions on the 2D SQIF array. The array dc bias can be fed uniformly from the top bi-SQUID row (cells 40.sub.1,1 through 40.sub.1,N of the 2D SQIF array 70). Similarly, the array can be grounded to the bottom bi-SQUID row (cells 40.sub.M,1 through 40.sub.M,N or array 70 in FIG. 7). The inductively coupled flux bias line is overlaid on the top of the array forming loops for each column. The direction of the de flux bias control current is from top to bottom of array 70 in FIG. 7. The 2-D array design in FIGS. 7-8 avoids the use of long parasitic wires, as every component of the array is an essential element of a bi-SQUID, which results in an efficient use of the available area.

(60) To account for the boundary conditions in an MN 2D array, and referring again to FIG. 7, The number of diamonds cells 40 in the vertical direction can be 2M and the number of bi-SQUIDs in the horizontal direction can be 2N-1. This means that, for example a 108 array can have 2015=300 bi-SQUIDs. The segmenting of the array in the manner allows for the smallest repeated pattern grouping, which can further result in the simplest set of modeling equations for computational purposes. The 2D array equations are derived in pieces that include the diamond structure and two transition areas, as shown by area 82 in FIG. 8a. This segmentation of the array is the smallest repeatable pattern.

(61) Using the above methodology, the equation for the 2D array cells in the interior of the array, i.e. cells 40.sub.j,i where j=2 to M-1 and i=2 to N-1 as shown in FIG. 8a results in the following equations (13) through (20) in Appendix found at the end of this Specification. Next, the methodology was used for the top row of cells 40.sub.j,i for j=1 and i=2, . . . , N-1 (FIG. 8c) resulting in the development of equations (21) through (28) of the Appendix. Still further, the methodology was used to develop the equations (29) through (36), which model the bottom row of cells 40.sub.j,i for j=M and i=2, . . . ,N-1 (FIG. 8h). In similar fashion, the equations that model the left side cells 40.sub.j,i for j=2, . . . , M-1 and i=1 (Equations (37) through (44), FIG. 8e), the top left hand corner cell 40.sub.1,1 (FIG. 8b and Equations (45) through (52)), the bottom left hand corner cell 40.sub.M,1 (FIG. 8g, Appendix Equations (53) through (60)) were developed. Finally, the equations for the rights side of array 70, cells 40.sub.j,i for j=2, . . . , M-1 and i=N of the array (FIG. 8f) were developed and listed as Equations (61) through (66) in the equations Appendix, and the equations for the top right hand corner cell 40.sub.1,N (FIG. 8d, Equations (67) through (72)), and bottom right hand corner cell 40.sub.M,N (FIG. 8i, Equations (73) through (78)) were developed. The net result is a matrix of sixty-six equations, Equations (13) through (78), which can accurately the behavior of the 2D SQIF array.

(62) As described above for a single cell 40, once Equations (13)-(78) are developed and solved for phases and phase rates (derivatives of ) for each JJ in each cell 40. These derivatives are used to calculate the average voltage response of the bi-SQUID array, which is the output measured from the fabricated bi-SQUID chips Next, the cell can be manufactured with the cell inductances that achieve the desired phase and phase rate (and by extension, the desired voltage response). The inductances, critical currents, normal state resistance, bias currents and external field are known or controllable. One way this has been accomplished in the prior art was by varying the loop size of bi-SQUID 20. But for SQIFarray 70, uniform loop sizes are needed for ease of manufacture of diamon cells 40 and 2D SQIF array 70. So, in order to vary the inductances in 2D SQIF array 70 while the a uniform loop size (area of the cell 40), the inductances, critical currents, normal state resistance, bias currents and external field are known or controllable. The arrays can be constructed by varying the area of triangle array cells 20 and ground plane hole sizes in a manner that reults in a normal Gaussian distribution of cell inductances.

(63) FIG. 9 shows layout implementation of a portion of the 8015 2D array of FIG. 7, using diamond dual bi-SQUID cells. The total area of the 2D array of dual-bi-SQUID cells shown in for an 8015 2D array can be 1623 m.sup.2. The central area of each cell 40 contains ground plane openings to facilitate RF signal reception.

(64) 2. Experimental Investigation 2D SQIF Noise Properties

(65) FIG. 10 illustrates the measured flux-to-voltage characteristics of a 1580 2D SQIF array of cell 40 of FIGS. 7-9, with a 70% Gaussian spread (=70%) of inductance values. Like FIG. 3 for SQUIDs and bi-SQUIDs, FIG. 10 is a graph of the average voltage, <V>, of the 2D SQIF array at a point in x.sub.e, which is the mean value of the voltage over time. As shown in FIG. 10, the measured flux/voltage characteristic for =70% is 50 mV/div 0.5 mA/div, max voltage=295 mV, V/I (flux bias) 735 V/A. FIGS. 11-13 show the corresponding flux noise measurement at the mid-point of the positive slope of the anti-peak (point 1002 of peak 1000 in FIG. 10). As can be seen from FIG. 11, the flux noise spectral density can approach 210.sup.6.sub.0/{square root over (Hz)}, which is the expected value for this size array. FIGS. 12 and 13 show the corresponding energy characteristics of the (1580) bi-SQUID SQIF array, which were calculated as follows:

(66) Noise energy per unit bandwidth via flux noise in a SQUID:

(67) $\begin{array}{cc}\mathrm{.Math.}\left(f\right)=\frac{S_{}\left(f\right)}{2L},& \left(79\right)\end{array}$
where f is frequency, Linductance of bi-SQUID calculated from the measured seperately I.sub.c modulations of the curve defined as

(68) $L=\frac{{}_0}{I_c};$
and,

(69) Noise temperature:

(70) $\begin{array}{cc}{T}_N=\frac{f\mathrm{.Math.}\left(f\right)}{k_B}& \left(80\right)\end{array}$
where k.sub.B is Boltzmann's constant.

(71) As shown by FIGS. 10-13, a well-defined zero-field anti-peak for a 2D SQIF array of cells 40 can be maintained if the mutual inductances between cells and the boundary conditions are accounted for. Stated differently, more bi-SQUID's can be packed into a corresponding areas using the methods of the present invention without sacrificing the overall linearity anti-peak response of the 2D SQIF array, when considered as a whole.

(72) 3. 2D SQIF Array Antenna Sensitivity Analysis

(73) The sensitivities illustrated in FIGS. 10-13 were based on a SQIF-based antenna, by assuming that the area for a single diamond shaped (double) bi-SQUID cell 40 is 1.6210.sup.9 m.sup.2. Using that as the effective area for cell 40, multiplying by 1580/2 to account for the number of individual bi-SQUIDs in the array, and taking the flux noise from FIG. 8(b) as 210.sup.6.sub.0/{square root over (Hz)}, gives a field sensitivity of 4.25 fT/{square root over (Hz)}. Assuming a scaling as a function of {square root over (N)}, the field noise for a 10002000 array would be 0.104 fT/{square root over (Hz)} at 100 kHz. Approximating the physical dimension of the diamond cell 40 as 71 m71 m means that the diamond occupies an area of 510.sup.9 m.sup.2 (consistent with the effective area of the diamond shaped bi-SQUID). Thus a 10002000 array would occupy an area of 50 cm.sup.2, since each diamond contains two bi-SQUIDs. This corresponds to a square with 7.1 cm on a side. A corresponding linear (1D) array of the prior art, which would essentially be 2,000,000 bi-SQUIDs that are meandered in series, would require a much larger area, an area of 10,562 cm.sup.2.

(74) Referring now to FIG. 14, a block diagram 100 that illustrates steps that can be taken to practice the methods of the present invention according to several embodiments is shown. As shown method 100 can include the initial step 102 of providing a plurality of bi-SQUID's 20. The bi-SQUIDs 20 can have the structure as described above. The methods can further include the step 104 of merging pairs of bi-SQUID's 20 into diamond-shaped cells 40 and connecting the ells so that each cell 40 shares at least three cell junctions 80 (step 106). Next, the methods according to several embodiments can include the step 108 of modeling the phases of the 2D SQIF array. Step 108 can further be accomplished by accounting for mutual inductances between cells 40 (step 110 in FIG. 14) and by using the equations (13) through (78) of the Appendix to model the boundarys conditions of array 70 (step 112 in FIG. 14). As shown by step 114 in FIG. 14, the methods according to several embodiments can further include the step of manufacturing cells 40 with inductances that achieve the phases and phase behavior resulting form the accomplishment of step 108, in order the achieve the anti-peak response shown in FIG. 10. For embodiments the loop size of cell 40 is uniform, one way to do this can be to vary the ground plane hole size, as discussed above.

(75) The use of the terms a and an and the and similar references in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms comprising, having, including, and containing are to be construed as open-ended terms (i.e., meaning including, but not limited to,) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

(76) Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

APPENDIX

2D Diamond Array Governing Equations

(77) For the model equations below, the variables .sub.m,i,j, m=1, . . . ,8, i=1, . . . , N, j=1, . . . , M are the phases on each of the Josephson junctions (m=1, . . . ,8). The dots denote the time differentiation with normalized time =.sub.ct, where t is time and

(78) ${}_c=\frac{2{\mathrm{eI}}_c{R}_N}{}$
is the normalized time constant. The parameter R.sub.N in .sub.c is the normal state resistance of the Josephson junctions, I.sub.c is the critical current of the Josephson junctions, e is the charge of an electron, and h is the reduced Planck constant.

(79) $i_b=\frac{I_b}{I_c}$
is the normalized bias current, where I.sub.b is the bias current.

(80) ${}_0\frac{h}{2e}2.07{10}^{-15}$
tesla meter squared is the flux quantum, where h is Plank's constant and 2e is the charge on the Cooper pair. The normalized critical current on the third junction is

(81) $i_{c3,i,j}=\frac{I_{c3,i,j}}{I_c},$
the normalized critical current of the sixth junction is

(82) $i_{c6,i,j}=\frac{I_{c6,i,j}}{I_c},$
the normalized critical current of the seventh junction is

(83) $i_{c7,i,j}=\frac{I_{c7,i,j}}{I_c},$
the normalized critical current of the eighth junction is

(84) 0$i_{c8,i,j}=\frac{I_{c8,i,j}}{I_c},$
I.sub.c1,i,j=I.sub.c2,i,j=I.sub.c4,i,j=I.sub.c5,i,j=I.sub.0,

(85) $x_{e,i,j}=\frac{B_e}{{}_0}$
is the normalized external magnetic flux per unit area and a.sub.n,i,j, n=1, . . . ,4 is the bi-SQUID area. The approximate assumptions that a.sub.1,i,j=L.sub.1,i,j+L.sub.2a,i,j+L.sub.2b,i,j, a.sub.2=L.sub.1,i,j+L.sub.5a,i,j+L.sub.5b,i,j, a.sub.3,i,j=L.sub.4,i,j+L.sub.2a,i+1,j+L.sub.2b,i,j, a.sub.4=L.sub.4,i,j+1+L.sub.5a,i+1,j+L.sub.5b,i,j are used.

(86) Using the assumptions and variables able, the equations for the array 70 interior cells, i.e, Cells 40.sub.j,i for j=2, . . . ,M-1 and i=2, . . . ,N-1 become (8 equations):

(87) $\begin{array}{cc}{L}_{2a,i,j}\left({\stackrel{.}{}}_{1,i,j}+{\stackrel{.}{}}_{1,i-1,j}-{\stackrel{.}{}}_{3,i,j}\right)-L_{2b,i,j}\left({\stackrel{.}{}}_{2,i,j}+{\stackrel{.}{}}_{3,i,j}-{\stackrel{.}{}}_{7,i,j}\right)+L_{1,i,j}\left(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,j}+\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{2,k,j}-{\stackrel{.}{}}_{3,i,j}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{4,k,j}-\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{5,k,j}-{\stackrel{.}{}}_{6,i,j}\right)={}_{2,i,j}-{}_{1,i,j}+2x_e{a}_{1,i,j}-L_{2a,i,j}\left(\sin {}_{1,i,j}+i_{c7,i-1,j}\sin {}_{7,i-1,j}-i_{c3,i,j}\sin {}_{3,i,j}\right)+L_{2b,i,j}\left(\sin {}_{2,i,j}+i_{c3,i,j}\sin {}_{3,i,j}-i_{c7,i,j}\sin {}_{7,i,j}\right)-L_{1,i,j}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,j}+\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{2,k,j}-i_{c3,i,j}\sin {}_{3,i,j}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{4,k,j}-\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{5,k,j}-i_{c6,i,j}\sin {}_{6,i,j}\right)& \mathrm{Equation}\left(13\right)\end{array}$

(88) $\begin{array}{cc}{L}_{2b,i,j}\left({\stackrel{.}{}}_{2,i,j}+{\stackrel{.}{}}_{3,i,j}-{\stackrel{.}{}}_{7,i,j}\right)-L_{2a,i,j}\left({\stackrel{.}{}}_{1,i+1,j}+{\stackrel{.}{}}_{7,i,j}-{\stackrel{.}{}}_{3,i+1,j}\right)-L_{4,i,j}\left(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{4,k,j-1}+\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{5,k,j-1}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,j}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{2,k,j}\right)={}_{1,i+1,j}-{}_{2,i,j}+2x_e{a}_{3,i,j}-L_{2b,i,j}\left(\sin {}_{2,i,j}+i_{c3,i,j}\sin {}_{3,i,j}-i_{c7,i,j}\sin {}_{7,i,j}\right)+L_{2a,i+1,j}\left(\sin {}_{1,i+1,j}+i_{c7,i,j}{\sin }_{7,i,j}-i_{c3,i+1,j}\sin {}_{3,i+1,j}\right)+L_{4,i,j}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{4,k,j-1}+\underset{k=1}{\overset{i}{.Math.}}\sin {}_{5,k,j-1}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,j}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{2,k,j}\right)& \mathrm{Equation}\left(14\right)\end{array}$
(L.sub.3a,i,j+L.sub.3b,i,j){dot over ()}.sub.3,i,j=.sub.2,i,j.sub.1,i,j.sub.3,i,j(L.sub.3a,i,j+L.sub.3b,i,j)i.sub.c3,i,j sin .sub.3,i,jEquation (15)

(89) $\begin{array}{cc}{L}_{5a,i,j}\left({\stackrel{.}{}}_{4,i,j}+{\stackrel{.}{}}_{6,i,j}-{\stackrel{.}{}}_{8,i-1,j}\right)-L_{5b,i,j}\left({\stackrel{.}{}}_{8,i,j}+{\stackrel{.}{}}_{5,i,j}-{\stackrel{.}{}}_{6,i,j}\right)-L_{1,i,j}\left(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,j}+\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{2,k,j}-{\stackrel{.}{}}_{3,i,j}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{4,k,j}-\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{5,k,j}-{\stackrel{.}{}}_{6,i,j}\right)={}_{5,i,j}-{}_{4,i,j}+2x_e{a}_{2,i,j}-L_{2a,i,j}\left(\sin {}_{4,i,j}+i_{c6,i,j}\sin {}_{6,i,j}-i_{c8,i-1,j}\sin {}_{8,i-1,j}\right)+L_{5b,i,j}\left(\sin {}_{5,i,j}+i_{c8,i,j}\sin {}_{8.i,j}-i_{c6,i,j}\sin {}_{6,i,j}\right)+L_{1,i,j}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,j}+\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{2,k,j}-i_{c3,i,j}\sin {}_{3,i,j}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{4,k,j}-\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{5,k.j}-i_{c6,i,j}\sin {}_{6,i,j}\right)& \mathrm{Equation}\left(16\right)\end{array}$

(90) $\begin{array}{cc}{L}_{5b,i,j}\left({\stackrel{.}{}}_{5,i,j}+{\stackrel{.}{}}_{8,i,j}-{\stackrel{.}{}}_{6,i,j}\right)-L_{5a,i+1,j}\left({\stackrel{.}{}}_{4,i+1,j}+{\stackrel{.}{}}_{6,i+1,j}-{\stackrel{.}{}}_{8,i,j}\right)+L_{4,i,j+1}(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{4,k,j}+\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{5,k,j}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,j+1}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{2,k,j+1})={}_{4,i+1,j}-{}_{5,i,j}+2x_e{a}_{4,i,j}-L_{5b,i,j}\left(\sin {}_{5,i,j}+i_{c8,i,j}\sin {}_{8,i,j}-i_{c6,i,j}\sin {}_{6,i,j}\right)+L_{5a,i+1,j}\left(\sin {}_{4,i+1,j}+i_{c6,i+1,j}\sin {}_{6,i+1,j}-i_{c8,i,j}\sin {}_{8,i,j}\right)-L_{4,i,j+1}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{4,k,j}+\underset{k=1}{\overset{i}{.Math.}}\sin {}_{5,k,j}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,j+1}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{2,k,j+1}\right)& \mathrm{Equation}\left(17\right)\end{array}$
(L.sub.6a,i,j+L.sub.6b,i,j){dot over ()}.sub.6,i,j=.sub.4,i,j.sub.5,i,j.sub.6,i,j(L.sub.6a,i,j+L.sub.6b,i,j)i.sub.c3,i,j sin .sub.3,i,jEquation (18)
(L.sub.7a,i,j+L.sub.7b,i,j){dot over ()}.sub.7,i,j+L.sub.2a,i+1,j({dot over ()}.sub.1,i+1,j+{dot over ()}.sub.7,i,j{dot over ()}.sub.3,i+1,j)L.sub.2b,i,j({dot over ()}.sub.2,i,j+{dot over ()}.sub.3,i,j{dot over ()}.sub.7,i,j)=.sub.7,i,j(L.sub.7a,i,j+L.sub.7b,i,j)i.sub.c7,i,j sin .sub.7,i,jL.sub.2a,i+1,j(sin .sub.1,i+1,j+i.sub.c7,i,j sin .sub.7,i,ji.sub.c3,i+1,j sin .sub.3,i+1,j)+L.sub.2b,i,j(sin .sub.2,i,j+i.sub.c3,i,j sin .sub.3,i,ji.sub.c7,i,j sin .sub.7,i,j)Equation (19)
(L.sub.8a,i,j+L.sub.8b,i,j){dot over ()}.sub.8,i,j+L.sub.5b,i,j({dot over ()}.sub.5,i,j+{dot over ()}.sub.8,i,j{dot over ()}.sub.6,i,j)L.sub.5b,i+1,j({dot over ()}.sub.4,i+1,j+{dot over ()}.sub.6,i+1,j{dot over ()}.sub.8,i,j)=.sub.8,i,j(L.sub.8a,i,j+L.sub.8b,i,j)i.sub.c8,i,j sin .sub.7,i,jL.sub.5b,i,j(sin .sub.5,i,j+i.sub.c8,i,j sin .sub.8,i,ji.sub.c6,i,j sin .sub.6,i,j)+L.sub.5a,i+1,j(sin .sub.4,i+1,j+i.sub.c6,i+1,j sin .sub.6,i+1,ji.sub.c8,i,j sin .sub.8,i,j)Equation (20)

(91) For the cells in the top row of array 70, i.e. for cells 40.sub.j,i for j=1 and i=2, . . . , N-1 (8 equations):

(92) $\begin{array}{cc}{L}_{2a,i,j}\left({\stackrel{.}{}}_{1,i,1}+{\stackrel{.}{}}_{7,i-1,1}-{\stackrel{.}{}}_{3,i,1}\right)-L_{2b,i,1}\left({\stackrel{.}{}}_{2,i,1}+{\stackrel{.}{}}_{3,i,1}-{\stackrel{.}{}}_{7,i,1}\right)+L_{1,i,1}\left(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,1}+\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{2,k,1}-{\stackrel{.}{}}_{3,i,1}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{4,k,1}-\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{5,k,1}-{\stackrel{.}{}}_{6,i,1}\right)={}_{2,i,1}-{}_{1,i,1}+2x_e{a}_{1,i,1}-L_{2a,i,1}\left(\sin {}_{1,i,1}+i_{c7,i-1,i}\sin {}_{7,i-1,1}-i_{c3,i,1}\sin {}_{3,i,1}\right)+L_{2b,i,1}\left(\sin {}_{2,i,1}+i_{c3,i,1}\sin {}_{3,i,1}-i_{c7,i,1}\sin {}_{7,i,1}\right)-L_{1,i,1}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,1}+\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{2,k,1}-i_{c3,i,1}\sin {}_{3,i,1}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{4,k,1}-\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{5,k,1}-i_{c6,i,1}\sin {}_{6,i,1}\right)& \mathrm{Equation}\left(21\right)\end{array}$

(93) $\begin{array}{cc}{L}_{2b,i,1}\left({\stackrel{.}{}}_{2,i,1}+{\stackrel{.}{}}_{3,i,1}-{\stackrel{.}{}}_{7,i,1}\right)-L_{2a,i+1,1}\left({\stackrel{.}{}}_{1,i+1,1}+{\stackrel{.}{}}_{7,i,1}-{\stackrel{.}{}}_{3,i+1,1}\right)+L_{4,i,1}\left(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,1}+\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{2,k,1}\right)=i{L}_{4,i,1}{i}_b+{}_{1,i+1,1}-{}_{2,i,1}+2x_e{a}_{3f,i,1}-L_{2b,i,1}\left(\sin {}_{2,i,1}+i_{c3,i,1}\sin {}_{3,i,1}-i_{c7,i,1}\sin {}_{7,i,1}\right)+L_{2a,i+1,1}\left(\sin {}_{1,i+1,1}+i_{c7,i,1}\sin {}_{7,i,1}-i_{c3,i+1,1}\sin {}_{3,i+1,1}\right)-L_{4,i,1}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,1}+\underset{k=1}{\overset{i}{.Math.}}\sin {}_{2,k,1}\right)& \mathrm{Equation}\left(22\right)\end{array}$
(L.sub.3a,i,1+L.sub.3b,i,1){dot over ()}.sub.3,i,1=.sub.2,i,1.sub.1,i,1.sub.3,i,1(L.sub.3a,i,1+L.sub.3b,i,1)i.sub.c3,i,1 sin .sub.3,i,1Equation (23)

(94) $\begin{array}{cc}{L}_{5a,i,1}\left({\stackrel{.}{}}_{4,i,1}+{\stackrel{.}{}}_{6,i,1}-{\stackrel{.}{}}_{8,1-i,1}\right)-L_{5b,i,1}\left({\stackrel{.}{}}_{8,i,1}+{\stackrel{.}{}}_{5,i,1}-{\stackrel{.}{}}_{6,i,j}\right)-L_{1,i,1}\left(\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{1,k,1}+\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{2,k,1}-{\stackrel{.}{}}_{3,i,1}-\underset{k=1}{\overset{i}{.Math.}}{\stackrel{.}{}}_{4,k,1}-\underset{k=1}{\overset{i-1}{.Math.}}{\stackrel{.}{}}_{5,k,1}-{\stackrel{.}{}}_{6,i,1}\right)={}_{5,i,1}-{}_{4,i,1}+2x_e{a}_{2,i,1}-L_{2a,i,1}\left(\sin {}_{4,i,1}+i_{c6,i,1}\sin {}_{6,i,1}-i_{c8,i-1,1}\sin {}_{8,i-1,1}\right)+L_{5b,i,1}\left(\sin {}_{5,i,1}+i_{c8,i,1}\sin {}_{8,i,1}-i_{c6,i,1}\sin {}_{6,i,1}\right)+L_{1,i,1}\left(\underset{k=1}{\overset{i}{.Math.}}\sin {}_{1,k,1}+\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{2,k,1}-i_{c3,i,1}\sin {}_{3,i,1}-\underset{k=1}{\overset{i}{.Math.}}\sin {}_{4,k,1}-\underset{k=1}{\overset{i-1}{.Math.}}\sin {}_{5,k,1}-i_{c6,i,1}\sin {}_{6,i,1}\right)& \mathrm{Equation}\left(24\right)\end{array}$