Abstract: A varactor based phase shifter that increases phase shift range using a lower characteristic impedance between quadrature ports than is used at its input/output ports. The circuit makes use of a four port coupler arrangement that imbeds a quarter wave impedance transformation between the input port and the quadrature ports as well as between the quadrature ports and the output port. The characteristic impedance across the quadrature ports is therefore less than the characteristic impedance across the input and output ports. In one implementation, reducing a characteristic input/output impedance of 50 to a 20 ohm quadrature port impedance results in a phase shift range increase of more than 50%.

Abstract: A scanned antenna array includes time delay stages each having at least one time delay sub-circuit. Each time delay sub-circuit includes a sub-circuit input, a sub-circuit output, a first delay line, and a second delay line. A first diode switch connects a first end of a selected one of the first and second delay lines to the sub-circuit input. A second diode switch connects a second end of the selected one of the first and second delay lines to the sub-circuit output. The sub-circuit output is connected to one of another time delay sub-circuit or to an output of the time delay stage. A respective transmit/receive (TR) module is coupled to an output of each time delay stage and issues a TR module output signal. A plurality of antenna elements radiate an output signal received from the corresponding TR module.

Abstract: A switched coupler type digital phase shifter using a quadrature generator is disclosed. A switched coupler type digital phase shifter includes: a coupling unit for receiving one input signal and generating a first signal and a second signal having 180 degree phase difference based on the received input signal; a quadrature signal generation unit for generating a third signal to a sixth signal having 90 degree phase difference to each other based on the first signal and the second signal outputted from the coupling unit; and a switching unit for selectively outputting one of the third signal to the sixth signal outputted from the quadrate signal generation unit in response to a control signal. The present invention can increased integration of the multi-bit digital phase shifter by implementing multi bit phase variant with only one phase shifter. Also, the insertion loss can be minimized.

Abstract: An electronically scanned slotted waveguide antenna radiates an RF signal as a scannable beam. The antenna has radiation waveguides positioned in an array. Radiation slots in the radiation waveguides radiate the scannable beam. A feed waveguide is coupled to the radiation waveguides. The feed waveguide feeds the RF signal to the radiation waveguides through coupling slots. The feed waveguide has sidewalls with tunable electromagnetic crystal (EMXT) structures thereon. The EMXT structures vary the phase of the RF signal in the feed waveguide to scan the radiated beam in one dimension. The radiation waveguides may also have tunable EMXT structures on the sidewalls to vary the phase of the RF signal to scan the radiated beam in a second dimension. The EMXT structures may be discrete EMXT devices or a EMXT material layer covering the feed and radiation waveguide sidewalls.

Abstract: A phase shifter according to this invention includes a circuit board having a semi-insulating layer. An active layer is formed in a transmission line forming portion on one surface side of the semi-insulating layer, a first ground conductive layer is formed on the other surface side, a transmission line is formed on the upper side of the active layer, and a second ground conductive layer is formed on the transmission line forming surface of the semi-insulating layer in close proximity to one side of the transmission line. If a bias voltage of negative polarity is applied to the transmission line, reverse bias is applied to the active layer to form a depletion layer and capacitance is equivalently connected to the transmission line having inductance. A phase shift amount can be freely controlled by changing the value of the capacitance according to the bias voltage.

Abstract: An in-band group delay equalizer is formed in a simple circuit configuration so as to have a flat group delay characteristic over a wide frequency band without having a peak of group delay near each passband edge. The in-band group delay equalizer includes a plurality of convex group delay circuits. Each convex group delay circuit is formed of one hybrid coupler and two resonators connected to respective divided output ports of the hybrid coupler. The center frequencies of the respective convex group delay circuits are set to be different from each other so that the overall group delay characteristic of the in-band group delay equalizer becomes flat. The bandwidth and the group delay can be easily adjusted. A distortion compensation amplifier with very low distortion can be realized using such an in-band group delay equalizer.

Abstract: A micro electro-mechanical system (MEMS) phase shifter for shifting the phase of a radio frequency (RF) signal. The phase shifter includes a quadrature coupler having an input port, an output port, a first load port and a second load port. A first variable reactance is coupled to the first load port and a second variable reactance is coupled the second load port. Each variable reactance has a plurality of reflecting phase shifting elements each having an associated micro electro-mechanical system (MEMS) switching element to individually and selectively couple the reflecting phase shifting element to the appropriate load port.

Abstract: A microwave frequency device includes: a first substrate having a dielectric layer and a conductive film disposed on opposing first and second sides of the dielectric layer, the conductive film on the first side of the dielectric layer of the first substrate including at least one signal line; and a second substrate having a dielectric layer, conductive film disposed on at least one of first and second opposing sides of the dielectric layer, and at least one cut-out where the dielectric layer and conductive film have been removed, wherein the first and second substrates are bonded together to form a bonded assembly such that (i) a portion of the signal line of the first substrate is sandwiched between the dielectric layers of the first and second substrates, and (ii) the at least one cut-out exposes a portion of the signal line, thereby forming a microstrip portion. A method of forming same is also disclosed.

Abstract: A varactor based phase shifter that increases phase shift range using a lower characteristic impedance between quadrature ports than is used at its input/output ports. The circuit makes use of a four port coupler arrangement that imbeds a quarter wave impedance transformation between the input port and the quadrature ports as well as between the quadrature ports and the output port. The characteristic impedance across the quadrature ports is therefore less than the characteristic impedance across the input and output ports. In one implementation, reducing a characteristic input/output impedance of 50 to a 20 ohm quadrature port impedance results in a phase shift range increase of more than 50%.

Abstract: A phase shift control voltage distribution scheme for a phased array utilizing voltage-proportional phase shift devices employs a digital-to-analog converter that supplies respectively different analog voltages to a sample-and-hold switch network coupled to analog voltage control inputs of the plurality of voltage-proportional phase shift devices. In order to impart a phase shift control voltage to one or more phase shift elements of the array, a control unit supplies a prescribed combination of a digital control code to the digital-to-analog converter and a switch control code to sample-and-hold switches of the switch network.

Abstract: In the present invention a multi-bit time-delay adjuster using Radio Frequency (RF) MicroElectroMechanical (MEM) switches is disclosed for applications in MCPAs with feed-forward linearization technique. The MEM switching system used in the multi-bit time-delay adjuster makes it possible to automatic control the time-delay match with very high precision required in feed-forward MultiCarrier Power Amplifiers (MCPA), instead of a manual trimming process. A searching process suitable for the automatic control of time-delay match is also introduced and demonstrated by an example of a four-bit time-delay adjuster.

Abstract: Provided is a broadband phase shifter using a coupled line and parallel open and short stubs. The broadband phase shifter of the present research has a new switching network structure by forming a coupled line, main transmission lines and parallel &lgr;/8 (45°) open and short stubs on both ends of the main transmission lines in order to obtain broadband phase characteristic that the phase difference between two networks is uniform.

Abstract: A transmission line includes a signal conductor and at least one varactor diode capacitively coupled to the signal conductor. The transmission line's signal path delay is a function of its shunt capacitance, and the varactor's capacitance forms a part of the transmission line's shunt capacitance. The transmission line's signal path delay is adjusted by adjusting a control voltage across the varactor diode thereby to adjust the varactor diode's capacitance.

Abstract: A broadband, 4-bit MMIC phase shifter for use in a phased array antenna is provided. The four bit selectable phase shifter for use in a phased array antenna of the present invention, which selectably causes an input signal to be shifted in phase, includes a first bit for selectively providing a 180° phase shift, wherein the first bit is a line/reflected bit; a second bit for selectively providing a 90° phase shift, wherein the second bit is a reflected bit; a third bit for selectively providing a 45° phase shift, wherein the third bit is a reflected bit; and a fourth bit for selectively providing a 22.5° phase shift, wherein the fourth bit is a high pass/low pass bit. The phase shifter of the present invention is compact, broadband and has good insertion loss and balance, yet uses a standard 0.25 mm PHEMT process with standard bias voltages.

Abstract: A multi-bit phase shifter suitably used for a satellite broadcasting and a satellite communication band includes one or a plurality of phase shifters each having a short stub with an end short and an MEMS (Micro Electro Mechanical System) switch formed at the end of the short stub and controlling an impedance value. A processing cost and an insertion loss can be reduced, a driving voltage can be lowered, a wider bandwidth can be obtained, and uniform phase characteristics can be obtained.

Abstract: Techniques enabling electronic control of propagation constant associated with meanderline loaded antennas and phased arrays are disclosed. An activation layer can be electronically stimulated to change its characteristics (e.g., capacitance or shape) so as to enable the control independent of antenna operating frequency.

Abstract: A phase shifter includes an FET 2a having its drain electrode connected to an input/output terminal 1a; an FET 2b having its drain electrode connected to the source electrode of the FET 2a and its source electrode connected to an input/output terminal 1b; an FET 2c having its drain electrode connected to the source electrode of the FET 2a; and an inductor 3a having its first terminal connected to the source electrode of the FET 2c and its second terminal connected to a ground. It can reduce the insertion loss by narrowing the gate width of the FET 2a, and carries out the phase shift of a high-frequency signal with suppressing the reflection.

Abstract: A phase shifter for switching passing phase of a high-frequency signal by means of ON/OFF control of a micro-machine switch, the micro-machine switch comprising cantilevers (11a), (11b) with one ends thereof connected to a second distributed constant line (3a), (3b) and the other ends thereof formed to be capable of coming toward and away from the other of a first distributed constant line (2a), (2b). The micro-machine switch further comprises a first insulating section formed in a region where the first distributed constant line (2a), (2b) faces the cantilevers (11a), (11b), and a second insulating section (15a), (15b) for keeping a voltage value of a first control signal together with the first insulating section.

Abstract: An RF phase shifter circuit includes first and second RF ports, and a switch circuit comprising a plurality of micro-electro-mechanical (“MEM”) switches responsive to control signals. The switch circuit is arranged to select one of a plurality of discrete phase shift values introduced by the phase shifter circuit to RF signals passed between the first and second RF ports. The circuits can be connected to provide a single-pole-multiple-throw (SPMT) or multiple-pole-multiple-throw (MPMT) switch function. The phase shifter circuits can be used in an electronically scanned array including a linear array of radiating elements, with an array of phase shifters coupled to the radiating elements. An RF manifold including a plurality of phase shifter ports is respectively coupled to a corresponding phase shifter RF port and an RF port. A beam steering controller provides phase shift control signals to the phase shifters to control the phase shift setting of the array of the phase shifters.

Abstract: A varactor based phase shifter that increases phase shift range using a lower characteristic impedance between quadrature ports than is used at its input/output ports. The circuit makes use of a four port coupler arrangement that imbeds a quarter wave impedance transformation between the input port and the quadrature ports as well as between the quadrature ports and the output port. The characteristic impedance across the quadrature ports is therefore less than the characteristic impedance across the input and output ports. In one implementation, reducing a characteristic input/output impedance of 50 to a 20 ohm quadrature port impedance results in a phase shift range increase of more than 50%.

Abstract: A phase shifter includes a first rat-race ring having four ports, an input coupled to a first one of the ports, an output coupled to a second one of the ports, a first resonant circuit coupled to a third one of the ports, and a second resonant circuit coupled to a fourth one of the ports, each of the first and second resonant circuits including a tunable dielectric varactor. The first rat race ring can be connected to another phase shifting stage including a second rat race ring or a digital switched line phase shifter.

Abstract: A scanned antenna array includes time delay stages each having at least one time delay sub-circuit. Each time delay sub-circuit includes a sub-circuit input, a sub-circuit output, a first delay line, and a second delay line. A first diode switch connects a first end of a selected one of the first and second delay lines to the sub-circuit input. A second diode switch connects a second end of the selected one of the first and second delay lines to the sub-circuit output. The sub-circuit output is connected to one of another time delay sub-circuit or to an output of the time delay stage. A respective transmit/receive (TR) module is coupled to an output of each time delay stage and issues a TR module output signal. A plurality of antenna elements radiate an output signal received from the corresponding TR module.

Abstract: A phase shifter according to this invention includes a circuit board having a semi-insulating layer. An active layer is formed in a transmission line forming portion on one surface side of the semi-insulating layer, a first ground conductive layer is formed on the other surface side, a transmission line is formed on the upper side of the active layer, and a second ground conductive layer is formed on the transmission line forming surface of the semi-insulating layer in close proximity to one side of the transmission line. If a bias voltage of negative polarity is applied to the transmission line, reverse bias is applied to the active layer to form a depletion layer and capacitance is equivalently connected to the transmission line having inductance. A phase shift amount can be freely controlled by changing the value of the capacitance according to the bias voltage.

Abstract: A phase shifter includes a substrate, a tunable dielectric film having a dielectric constant between 70 to 600, a tuning range of 20 to 60%, and a loss tangent between 0.008 to 0.03 at K and Ka bands positioned on a surface of the substrate, a coplanar waveguide positioned on a surface of the tunable dielectric film opposite the substrate, an input for coupling a radio frequency signal to the coplanar waveguide, an output for receiving the radio frequency signal from the coplanar waveguide, and a connection for applying a control voltage to the tunable dielectric film. A reflective termination coplanar waveguide phase shifter including a substrate, a tunable dielectric film having a dielectric constant between 70 to 600, a tuning range of 20 to 60%, and a loss tangent between 0.008 to 0.

Abstract: A voltage tunable dielectric varactor includes a substrate having a low dielectric constant and having generally planar surface, a tunable ferroelectric layer positioned on the generally planar surface of the substrate, and first and second electrodes positioned on a surface of the tunable ferroelectric layer opposite the generally planar surface of the substrate. The first and second electrodes are separated to form a gap therebetween. The varactor includes an input for receiving a radio frequency signal and an output for delivering the radio frequency signal. A bias voltage applied to the electrodes changes the capacitance of the varactor between the input and output thereof. Phase shifters and filters that include the varactor are also described.

Abstract: A switched loop RF radiator circuit, comprising a radiator element, a RF input/output (I/O) port, and a balun coupled between the radiator element and the (I/O) port. The balun includes a 180° switched loop circuit having transmission line legs coupled to a balun transition to provide a selectable phase shift, and a microelectromechanically machined (MEM) switch Many radiator circuits can be deployed in an electronically scanned antenna array.

Abstract: A miniaturized phase shifter and a multi-bit phase shifter are provided, in which filters are constructed using capacitors at FET pinch-off and pass phase can be shifted by turning the FET on and off, the phase shifter including: a first FET having a drain electrode connected to an input terminal and a source electrode connected to an output terminal; a second FET, in which one of a drain electrode and a source electrode thereof is connected to the source electrode of the first FET and the other is connected to ground via a first inductor; and a third FET, in which one of a drain electrode and a source electrode thereof is connected to the drain electrode of the first FET and the other is connected to ground via a second inductor.

Abstract: A phase shifter for changing the phase of a signal fed thereto. The phase shifter includes an inductive reactance element and a capacitive reactance element having one electrode connected to either the input or the output port and a pair of switching elements. A first switching element thereof switches between a conducting state and a non-conductive state when the control signal changes from a first logic state to a second logic state while a second switching element thereof switches between a non-conducting state and a conductive state when the control signal changes from the first logic state to the second logic state.

Abstract: A delay circuit for the secondary path of a feed-forward high power amplifier is disclosed. A first 3 dB quadrature hybrid coupler is coupled to first and second resonator circuits that are resonant at a first resonant frequency. The output of the first hybrid coupler is coupled to the input of a second 3 dB quadrature hybrid coupler. The second hybrid coupler is coupled to third and fourth resonator circuits that are resonant at a second resonant frequency that is greater than the first resonant frequency. The overall combined delay response of the first hybrid coupler and the second hybrid coupler appearing at the fourth node of the second hybrid coupler is substantially constant between the first resonant frequency and the second resonant frequency.

Abstract: A switched loop RF radiator circuit, comprising a radiator element, a circuit RF input/output (I/O) port, and a balun coupled between the radiator element and the I/O port. The balun includes a 180° switched loop circuit having two transmission line legs coupled to a balun transition to provide a selectable 180° phase shift, and a microelectromechanically machined (MEM) switch cirtuit. Many radiator circuits can be deployed in an electronically scanned antenna array.

Abstract: A phase shifter includes a comb-line defined by first and second transmission lines that are electromagnetically coupled with each other and a plurality of variable-capacitance diodes connected to the first and second transmission lines defining the comb-line. In the phase shifter, one end of the first transmission line is connected to an input terminal, one end of the second transmission line is connected to an output terminal, and the variable-capacitance diodes are connected between the other ends of the first and second transmission lines and the corresponding grounds.

Abstract: A delay circuit for the secondary path of a feed-forward high power amplifier is disclosed. A first 3 dB quadrature hybrid coupler is coupled to first and second resonator circuits that each includes a varactor circuit and are resonant at a first resonant frequency. The output of the first hybrid coupler is coupled to the input of a second 3 dB quadrature hybrid coupler. The second hybrid coupler is coupled to third and fourth resonator circuits that each includes a varactor circuit and are resonant at a second resonant frequency that is greater than the first resonant frequency. The overall combined delay response of the first hybrid coupler and the second hybrid coupler appearing at the fourth node of the second hybrid coupler is substantially constant between the first resonant frequency and the second resonant frequency.

Abstract: An apparatus comprising a first calibration circuit and a phase shift network stage. The first calibration circuit may be configured to generate a control signal. The phase shift network stage may comprise one or more tunable phase shift elements and be configured to provide a tunable impedance. The phase shift network stage may be tuned in response to the control signal and a conductance of the tunable phase shift elements.

Abstract: A phase shifter for changing the phase of a signal fed thereto. The phase shifter includes a first inductive reactance element and a first capacitive reactance element having one electrode connected to either the input or the output port. The phase shifter includes a first pair of switching elements. A first switching element thereof switches between a conducting state and a non-conductive state when the control signal changes from a first logic state to a second logic state while a second switching element thereof switches between a non-conducting state and a conductive state when the control signal changes from the first logic state to the second logic state. Also provided is a second pair of switching elements.

Abstract: A transmit/receive module including digitally controlled analog circuits is described. The digital circuits use a logic family adapted for use with analog monolithic integrated circuits. The disclosure also describes a preferred process to provide digital and analog microwave circuits on a common semiconductor substrate.

Abstract: In a phase shifter for digitally shifting the phase of an RF (Radio Frequency) signal by changing a switched line which is connecting two main lines into another switched line, at least one of the switched lines is always connected to one of the main lines so as to operate as an open stub when the RF signal is not passed through the switched line.

Abstract: A voltage tunable dielectric varactor includes a substrate having a low dielectric constant and having generally planar surface, a tunable ferroelectric layer positioned on the generally planar surface of the substrate, and first and second electrodes positioned on a surface of the tunable ferroelectric layer opposite the generally planar surface of the substrate. The first and second electrodes are separated to form a gap therebetween. The varactor includes an input for receiving a radio frequency signal and an output for delivering the radio frequency signal. A bias voltage applied to the electrodes changes the capacitance of the varactor between the input and output thereof. Phase shifters and filters that include the varactor are also described.

Abstract: A phase shifter includes a first rat-race ring having four ports, an input coupled to a first one of the ports, an output coupled to a second one of the ports, a first resonant circuit coupled to a third one of the ports, and a second resonant circuit coupled to a fourth one of the ports, each of the first and second resonant circuits including a tunable dielectric varactor. The first rat race ring can be connected to another phase shifting stage including a second rat race ring or a digital switched line phase shifter.

Abstract: A miniaturized phase shifter and a multi-bit phase shifter are provided, in which filters are constructed using capacitors at FET pinch-off and pass phase can be shifted by turning the FET on and off, the phase shifter including: a first FET having a drain electrode connected to an input terminal and a source electrode connected to an output terminal; a second FET, in which one of a drain electrode and a source electrode thereof is connected to the source electrode of the first FET and the other is connected to ground via a first inductor; and a third FET, in which one of a drain electrode and a source electrode thereof is connected to the drain electrode of the first FET and the other is connected to ground via a second inductor.

Abstract: A phase shifter comprises a coarse phase tuning arrangement and a fine phase tuning arrangement. The coarse phase tuning arrangement provides a discrete number of phase shifts. The fine phase tuning arrangement includes a RLC network, having a resistor, an inductor and a capacitor. The fine phase tuning arrangement also comprises an optical arrangement for varying the resistance value of the resistor. This phase shifter is able to obtain broadband, continuous 360° phase shifting also at Gigahertz frequencies. It also allows close to linear phase shift versus frequency resulting in true time delay capability, very low insertion loss and high value of maximum phase adjust.

Abstract: A voltage tunable dielectric varactor includes a substrate having a low dielectric constant and having generally planar surface, a tunable ferroelectric layer positioned on the generally planar surface of the substrate, and first and second electrodes positioned on a surface of the tunable ferroelectric layer opposite the generally planar surface of the substrate. The first and second electrodes are separated to form a gap therebetween. The varactor includes an input for receiving a radio frequency signal and an output for delivering the radio frequency signal. A bias voltage applied to the electrodes changes the capacitance of the varactor between the input and output thereof. Phase shifters and filters that include the varactor are also described.

Abstract: An improved accuracy phase shifter having cascaded phase shifting modules is provided for phase shifting a pulse train which rather than utilizing two pairs of control voltage leads for each phase shifting module, utilizes only one pair to significantly reduce the electromagnetic interference between the cascaded phase shifting modules. The result is that the phase of an incoming pulse train can be shifted from 0 to 360° in 3° increments with +/−1° accuracy. When the subject phase shifter is utilized in long haul fiber-optic cable networks operating at 10 gigabits/sec. for correcting phase offsets of data streams transmitted over ultra long distances, the utilization of the subject phase shifter plays a part in obviating the necessity of having regeneration units every 70 to 100 miles, thus permitting error-free transmission over as many as 2500 miles without the requirement for regeneration.

Abstract: A phase control device, for providing a plurality of phase values, for utilization by any system having a number of input/output ports with signals requiring control of their relative phases. The phase control device is constructed from phase shift elements electrically connected to a system of electrically interconnected switches separated off from the phase shift elements. The result is a reduction in the number of phase shift elements and switches as compared to conventional phase shifters and a simplification of the resulting architecture, a feature of significant importance in chip miniaturization.

Abstract: A phase shifter comprises a coarse phase tuning arrangement and a fine phase tuning arrangement. The coarse phase tuning arrangement provides a discrete number of phase shifts. The fine phase tuning arrangement includes a RLC network, having a resistor, an inductor and a capacitor. The fine phase tuning arrangement also comprises an optical arrangement for varying the resistance value of the resistor. This phase shifter is able to obtain broadband, continuous 360° phase shifting also at Gigahertz frequencies. It also allows close to linear phase shift versus frequency resulting in true time delay capability, very low insertion loss and high value of maximum phase adjust.

Abstract: A broadband, 4-bit MMIC phase shifter for use in a phased array antenna is provided. The four bit selectable phase shifter for use in a phased array antenna of the present invention, which selectably causes an input signal to be shifted in phase, includes a first bit for selectively providing a 180° phase shift, wherein the first bit is a line/reflected bit; a second bit for selectively providing a 90° phase shift, wherein the second bit is a reflected bit; a third bit for selectively providing a 45° phase shift, wherein the third bit is a reflected bit; and a fourth bit for selectively providing a 22.5° phase shift, wherein the fourth bit is a high pass/low pass bit. The phase shifter of the present invention is compact, broadband and has good insertion loss and balance, yet uses a standard 0.25 mm PHEMT process with standard bias voltages.

Abstract: A varactor based phase shifter that increases phase shift range using a lower characteristic impedance between quadrature ports than is used at its input/output ports. The circuit makes use of a four port coupler arrangement that imbeds a quarter wave impedance transformation between the input port and the quadrature ports as well as between the quadrature ports and the output port. The characteristic impedance across the quadrature ports is therefore less than the characteristic impedance across the input and output ports. In one implementation, reducing a characteristic input/output impedance of 50 to a 20 ohm quadrature port impedance results in a phase shift range increase of more than 50%.

Abstract: A semiconductor structure having a substrate, an insulator above a portion of the substrate, a conductor above the insulator; and at least two contact regions in the substrate on opposite sides of the portion of the substrate, wherein a voltage between the contact regions modulates a capacitance of the conductor.

Abstract: The present invention provides systems and methods for phase shifting signals wherein the phase shifting circuitry may be disposed in a relatively small footprint. The preferred embodiment utilizes PIN diodes to provide switched line phase shifting, wherein the switched lines are microstrip and/or stripline transmission lines of predetermined lengths. To minimize the space required, the switched lines of the preferred embodiment are disposed on different layers of a multi-layered support structure, such as a multi-layer circuit board. Layer changing vias are preferably adapted to provide a constant impedance to thereby make changes in layers in the transmission path electrically transparent to a transmitted signal.

Abstract: A phase shifter includes a comb-line defined by first and second transmission lines that are electromagnetically coupled with each other and a plurality of variable-capacitance diodes connected to the first and second transmission lines defining the comb-line. In the phase shifter, one end of the first transmission line is connected to an input terminal, one end of the second transmission line is connected to an output terminal, and the variable-capacitance diodes are connected between the other ends of the first and second transmission lines and the corresponding grounds.

Abstract: To make a variable phase shifter at low cost and that is easy to manufacture, two propagation paths for a high frequency signal are provided in parallel between the input and the output of the phase shifter. These two paths are of different lengths. An intermediate node on one of the paths is connected to an intermediate node on the other path by a PIN diode. The diode is connected to the paths by a segment of line further enhancing the length difference. By biasing the diode to a desired level, it is caused to present a particular impedance to propagation. It is shown that by acting in this way the diode can vary the phase shift between the input and the output without needing to use harmful reactive components.