A digital isolator can include: an encoding circuit configured to receive an input digital signal, and to encode a rising edge and a falling edge of the input digital signal into different coded signals; an isolating element coupled to encoding circuit, and being configured to transmit the coded signal in an electrical isolation manner; and a decoding circuit configured to receive the coded signal through the isolation element, and to decode the coded signal to obtain the rising edge and the falling edge, in order to output an output digital signal consistent with the input digital signal, where the rising edge of the input digital signal is encoded as a first pulse sequence, and the falling edge of the input digital signal is encoded as a second pulse sequence different from the first pulse sequence.

A passive circulator utilizing sequentially-switched delay lines (SSDL) in which delay line sections are sequentially turned on and off to achieve non-reciprocity to provide rejection/separations between different signals at the same/similar frequency, such as between a transmitted and received signal. The circulator is well-suited for on-chip integration and can be utilized across a wide frequency range. Various embodiments are described for separating signal waveforms.

Some variations provide a magnetically anisotropic structure comprising a hexaferrite film disposed on a substrate, wherein the hexaferrite film contains a plurality of discrete and aligned magnetic hexaferrite particles, wherein the hexaferrite film is characterized by an average film thickness from about 1 micron to about 500 microns, and wherein the hexaferrite film contains less than 2 wt % organic matter. The hexaferrite film does not require a binder. Discrete particles are not sintered or annealed together because the maximum processing temperature to fabricate the structure is 500° C. or less, such as 250° C. or less. The magnetic hexaferrite particles may contain barium hexaferrite (BaFe.sub.12O.sub.19) and/or strontium hexaferrite (SrFe.sub.12O.sub.19). The hexaferrite film may be characterized by a remanence-to-saturation magnetization ratio of at least 0.7. Methods of making and using the magnetically anisotropic structure are also described.

Apparatus and methods related to ferrite based circulators are disclosed. A ferrite disk used in a circulator can be configured to reduce intermodulation distortion when routing radio-frequency signals having closely spaced frequencies. Such a reduction in intermodulation distortion can be achieved by adjusting magnetization at the edge portion of the ferrite disk. By way of an example, a ferrite disk with a reduced saturation magnetization (4PiMs) edge portion can reduce intermodulation distortion. Example configurations with such a reduced 4PiMs edge portions are disclosed.

Apparatus and methods related to ferrite based circulators are disclosed. A ferrite disk used in a circulator can be configured to reduce intermodulation distortion when routing radio-frequency signals having closely spaced frequencies. Such a reduction in intermodulation distortion can be achieved by adjusting magnetization at the edge portion of the ferrite disk. By way of an example, a ferrite disk with a reduced saturation magnetization (4PiMs) edge portion can reduce intermodulation distortion. Example configurations with such a reduced 4PiMs edge portions are disclosed.

A non-reciprocal circuit element includes a ferrite, a first central electrode and a second central electrode that are arranged on the ferrite so as to cross each other in an insulated state, and a permanent magnet configured to apply a DC magnetic field to a portion where the first and second central electrodes cross each other. One end of the first central electrode defines an input port and the other end thereof defines an output port. One end of the second central electrode defines the input port and the other end thereof defines a ground port. A resistance element and a capacitance element which are connected in parallel with each other are connected in series between the input port and the output port. A switching capacitance unit configured to switch a capacitance is connected in parallel with the resistance element between the input port and the output port.

A non-reciprocal circuit element includes a ferrite, a first central electrode and a second central electrode that are arranged on the ferrite so as to cross each other in an insulated state, and a permanent magnet configured to apply a DC magnetic field to a portion where the first and second central electrodes cross each other. One end of the first central electrode defines an input port and the other end thereof defines an output port. One end of the second central electrode defines the input port and the other end thereof defines a ground port. A resistance element and a capacitance element which are connected in parallel with each other are connected in series between the input port and the output port. A switching capacitance unit configured to switch a capacitance is connected in parallel with the resistance element between the input port and the output port.

Favorable isolation characteristics are obtained over a wide band in a non-reciprocal circuit element. A non-reciprocal circuit element includes: a magnetic material 10 to which a DC magnetic field is applied by a permanent magnet; and a plurality of center electrodes disposed on the magnetic material 10 so as to intersect each other in an insulated state. Of the plurality of center electrodes, a first center electrode 21 is connected at one end thereof to a first input/output port P1, and a second center electrode 22 is connected at one end thereof to a second input/output port P2. A resistance element R is connected in series between the ports P1 and P2, and a phase-shift circuit (a parallel resonant circuit composed of an inductance element L5 and a capacitance element C5) is connected in series with the resistance element R.

Favorable isolation characteristics are obtained over a wide band in a non-reciprocal circuit element. A non-reciprocal circuit element includes: a magnetic material 10 to which a DC magnetic field is applied by a permanent magnet; and a plurality of center electrodes disposed on the magnetic material 10 so as to intersect each other in an insulated state. Of the plurality of center electrodes, a first center electrode 21 is connected at one end thereof to a first input/output port P1, and a second center electrode 22 is connected at one end thereof to a second input/output port P2. A resistance element R is connected in series between the ports P1 and P2, and a phase-shift circuit (a parallel resonant circuit composed of an inductance element L5 and a capacitance element C5) is connected in series with the resistance element R.

Disclosed are embodiments of synthetic garnet materials for use in radiofrequency applications. In some embodiments, increased amounts of bismuth can be added into specific sites in the crystal structure of the synthetic garnet in order to boost certain properties, such as the dielectric constant and magnetization. Accordingly, embodiments of the disclosed materials can be used in high frequency applications, such as in base station antennas.