Actuated pin antenna reflector

Abstract

Apparatus for improving the performance and allowing increased directionality of reflecting-type antenna systems by varying the geometry of the reflecting surface. A reflecting surface is composed of an array of actuated pins which are capable of extending or retracting to alter the overall pattern. An actuator controlling unit has the address of each actuator and is able to extend or retract the pins to the desired degree. The specific pattern which the actuator control unit realizes is determined by the iterative position calculator which utilizes directional inputs from the user and/or inputs from a system which determines the effectiveness of previous pin movements. The apparatus attempts to maximize the received signal by assessing amplitude changes over time and utilizing that information to direct alteration in the reflecting surface for optimal performance.

Claims

1. A variable geometry reflecting antenna apparatus, comprising: an anechoic backplane; a plurality of pins each having a head and a shaft, said shaft protruding through said anechoic backplane at a substantially perpendicular orientation to said anechoic backplane; an actuator connected to each said shaft, wherein said actuator displaces said shaft in a linear manner so as to vary the distance between said head and said anechoic backplane; a control system for controlling said actuators further comprising an actuator control unit; an iterative position calculator; a time bin generator; a high speed memory; and an amplitude comparator module; wherein said time bin generator quantizes and splits data corresponding to said received signal into time bins; said high speed memory delays said quantized data from said time bin generator by one timing bin; and said amplitude comparator module compares the amplitude of said delayed quantized data from said high speed memory to the amplitude of a subsequent quantized data from said time bin generator; computes an amplitude difference; time stamps said amplitude difference; and communicates said time stamped amplitude difference with said reflector control; a reflector control; wherein said reflector control compares previous pin positions to measurements of a received signal corresponding thereto; and current directivity commands: said iterative position calculator determines subsequent pin positions by performing numeric approximation on said pin position and signal strength received from said reflector control; and said actuator control unit commands said actuators in response to said pin positions received from said iterative position calculator.

2. The apparatus of claim 1, wherein said time-stamped amplitude difference is compared with pin position versus time data.

3. A variable geometry reflecting antenna apparatus, comprising: an anechoic backplane; a plurality of pins each having a head and a shaft, said shaft protruding through said anechoic backplane at a substantially perpendicular orientation to said anechoic backplane; a contact surface incorporated into each said shaft; a plurality of signal feeds incorporated into said anechoic backplane, each said signal feed corresponding to each said contact surface; an actuator connected to each said shaft, wherein said actuator displaces said shaft in a linear manner so as to vary the distance between said head and said anechoic backplane; an impedance matching network for matching the impedance of a signal path from said pins, said contact surfaces and said signal feeds to a transmit and receive signal source; and a control system for controlling said actuators; wherein said actuator displacement of said shaft establishes and disestablishes radio frequency signal contact between said contact surface and said signal feed.

4. The apparatus of claim 3, wherein said control system further comprises; an actuator control unit; an iterative position calculator; and a reflector control; wherein said reflector control compares previous pin positions to measurements of a received signal corresponding thereto; and current directivity commands; said iterative position calculator determines subsequent pin positions by performing numeric approximation on said pin position and signal strength received from said reflector control; and said actuator control unit commands said actuators in response to said pin positions received from said iterative position calculator.

5. The apparatus of claim 3, wherein said control system further comprises; a time bin generator; a high speed memory; and an amplitude comparator module; wherein said time bin generator quantizes and splits data corresponding to said received signal into time bins; said high speed memory delays said quantized data from said time bin generator by one timing bin; and said amplitude comparator module compares the amplitude of said delayed quantized data from said high speed memory to the amplitude of a subsequent quantized data from said time bin generator; computes an amplitude difference, time stamps said amplitude difference; and communicates said time stamped amplitude difference with said reflector control.

6. The apparatus of claim 4, wherein a time-stamped amplitude difference is compared with pin position versus time data.

7. The apparatus of claim 3, wherein said iterative position calculator accepts directional control inputs directly so as to alter the position of said plurality of pins.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram representation of the preferred embodiment of the present invention pin actuation system.

(2) FIG. 2 is a schematic diagram representation of the preferred embodiment of the present invention reflecting transmit and receive system.

(3) FIG. 3 depicts the received signal from the radio's Rx/Tx interface to the present invention's Time Bin Generator.

(4) FIG. 4 is a schematic diagram of the alternate embodiment of the present invention showing the signal feed system as well as the Impedance Matching Network.

(5) FIG. 5 is an image of the initial, manually operated test unit of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(6) Referring now to FIG. 1, FIG. 2, and FIG. 3 describes the preferred embodiment of the present invention.

(7) FIG. 1 shows a detail of the overall system illustrating the main novel points of the present invention. The broad head pins 100 make up the reflecting surface and it is the adjustment of the position of these pins which yields alterable overall geometry of the reflector. Behind the array of pins is an anechoic backplane 110 which helps isolate the reflecting surface and reduce any unwanted secondary reflections. Behind the backplane the pins are each attached to a precise, electrically controlled linear actuator 120 which serves as the motivator for the individual pins. In order to control the whole array of actuators the Actuator Control Unit (ACU) 130 contains the addressing and interface for each actuator, and is able to send the correct control signal to the correct actuator for any given position set. It also time-stamps the start and stop for pin movement time, and sends this Time Stamp Data created by Time Bin Start Gates 260 to the Iterative Position Calculator 140. The position set the ACU 130 will realize at any one point in time is determined by the Iterative Position Calculator 140 which takes inputs from the RF components of the system through the Reflector Control I/O 150 (see FIG. 2). The IPC 140 first uses ACU 130 and Amplitude Comparator Module 210 time stamp data to calculate if change in received signal amplitude is due to pin 100 position or inherent signal alterations. It then uses genetic algorithms to determine what the next reflector geometry should be based on the difference in system receive quality from the prior alteration of the reflector configuration, a difference calculated from signals sent by the Amplitude Comparator Module 210 and the time stamp information from the ACU 130. The IPC 140 is also able to accept directional control inputs from the system user which allows the system to alter the geometry of the reflector to receive or transmit in a specific direction. The Reflector Control I/O 150 converts the Amplitude Comparator Module 210 information into the proper format for the IPC 140 and transfers the data.

(8) FIG. 2 shows how the radio frequency (RF) components of the preferred embodiment fits into the previously described section. The incoming RF signal 160 to be received strikes the reflecting surface formed by the array of pins 100 and is reflected into the receive feed-horn 170. The feed-horn and Receive/Transmit (Rx/Tx) interface 180 can be built around any of a number of prior art systems.

(9) Referring to FIG. 3, the received signal from the radio's Rx/Tx interface 180 to the present invention is then input to the Time Bin Generator 190 where the data is split into time bins separated by Time Bin Start Gates 260. Referring back to FIG. 2, the received data is now separated into quantized segments as seen as the output of the Time Bin Generator 190. This formatted data, now isolated into segments by time bins, is sent to two places: the High-Speed Memory 200 and the Amplitude Comparator Module (ACM) 210. The High-Speed Memory 200 delays the received signal one timing bin and sends it on to the ACM 210 where it is compared to the next bin (i.e. the n.sup.th bin from the memory is compared with the n+1.sup.th bin from the Time Bin Generator 190 at the same time that the n+1.sup.th bin is saved to compare with the n+2 bin). The ACM 210 compares the relative amplitude of the receive signals in the different Time Bins to give an amplitude difference, it then time stamps this data for later comparison with pin motion position time gained from the Actuator Control Unit (see FIG. 1, 130), and sends it on to the Reflector Control I/O 150.

DETAILED DESCRIPTION OF AN ALTERNATE EMBODIMENT

(10) Referring to FIG. 4, and FIG. 5 simultaneously, depicts an alternate embodiment of the present invention and its test article implementation, respectively, whereby the feedhorn 170 (see FIG. 1) and reflector system of RF transmission and reception are replaced through use of the pins 100 themselves. In this embodiment the actuated pins 100 have Contact Surfaces 230 which, when the pins 100 are actuated forward, make contact with Signal Feeds 220 that make up a Signal Feed Network 240. This network connects to the Rx/Tx interface 180 via an Impedance Matching Network 250, allowing the individual broad head elements of the pins 100 to act as radiating elements. When the Actuators 120 pull the pins 100 and their attached Contact Surfaces 230 away from the Signal Feeds 220, it breaks the contact and ensures the pin 100 in question will not radiate. In this way the Actuator Control Unit 130, working with the Impedance Matching Network 250 to reduce impedance mismatch, ensure that the proper set of pins 100 are part of the radiating element so that the overall geometry of the element is tuned as desired.

(11) Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.