Hittite Microwave Corporation

Raytheon Company

Yalcin Ayasli

Peter John Katzin

Toshikazu Tsukii

Leonard D Reynolds

Brian E Bedard

A post launch identification friend or foe fire control system for a munition has an identification and ranging interrogation unit for mounting on a munition. The interrogation unit transmits an interrogation unit which detects and verifies an incoming identification code from a remote transponder unit in reply to the interrogation code. The range of the remote transponder is determined and a decision signal is provided to the fire control circuit of the munition to enable it to avoid a friendly target; a transponder unit receives the rf carrier signal containing an incoming interrogation code from an interrogation unit on board a munition, validates the incoming interrogation code, and extracts a timing signal from it. An identification code is synchronously generated with the incoming interrogation code using the timing signal. The synchronized identification code is then transmitted back to the interrogation unit on board the munition to confirm the identification of the transponder unit and its range.

Post launch on-board identification friend or foe system

A negative resistance generator includes first and second terminals; first and second inductors connected in series between the terminals; and a semiconductor amplifying device having a first control electrode connected to the first terminal and a first active electrode connected to the second terminal and a second active electrode connected to the junction of the inductors. When employed in an active filter resonator a first variable capacitor is interconnected with the inductors for setting the resonant frequency of the resonator. The resonators may be combined in an active filter with a transmission line where each of the resonators is interconnected to the line by decreasing resistance from the input to the output in order to balance the rf currents to which the resonators are subjected. An improved dual loop active filter control system is achieved by using a master oscillator that employs a resonator that is matched to the active filter resonator in the filter and servoing the frequency and Q-factor controls so that the drive signals are compensated for temperature drifts, manufacturing tolerances, and other problems while a buffer amplifier is used between the master oscillator and the frequency and gain control loops for isolating the master oscillator reference circuit from the loading of the loops and from the perturbation introduced by the frequency reference signal; a frequency shifting circuit in the frequency control loop permits the reference signal to be shifted to a lower or higher frequency than that of the master oscillator.

Active filter resonator and system and negative resistance generator

A switching system for controlling rf energy through an rf transmission medium including a plurality of semiconductor switching devices connected in a series configuration with the primary electrodes connected in series, and means for providing graduated bias on the control electrodes for establishing an equal control voltage on each device between its control electrode and one of its primary electrodes.

High-power rf switching system

A power FET includes a substrate of semi-insulating material having a top side and a ground side; an FET fabricated on the ground side of the substrate; and conductor means in the substrate extending from the drain electrode and the gate electrode on the ground side to the top side of the substrate. A ground plane on the ground side of the substrate contacts the source electrode of the FET and is spaced from the gate and drain electrodes to form a dome for minimizing ground inductance and maximizing heat transfer from the FET independent of the thickness of the substrate.

High-power FET circuit

A compact low pass/high pass filter phase shifter including a semiconductor switch having a control electrode and first and second load electrodes; a first inductance connected in series with one load electrode and second inductance connected in series with the other load electrode; a third inductance connected in parallel with one load electrode to ground and a fourth inductance connected in parallel with the other load electrode to ground; a capacitance connected in series between the control electrode and ground; and means for applying a control signal to the control electrode for switching the semiconductor switch between a first state in which it operates as a low pass filter and a second state in which it operates as a high pass filter to introduce a phase shift in a propagated signal.

Low pass/high pass filter phase shifter

A non-reciprocal bidirectional duplexer includes a first transmission medium extending from a first terminal to a third terminal; a second transmission medium extending from the second terminal to the third terminal; and a plurality of non-reciprocal, bidirectional phase shifting elements, coupling the transmission mediums and spaced along them; each of the phase shifting elements includes means for amplifying a signal in a first direction from the first to the second transmission medium and for amplifying a signal in the second direction from the second to the first transmission medium; and means for establishing a phase differential between the signals moving in the first and second directions.

Non-reciprocal bidirectional duplexer

A cascaded low pass/high pass filter phase shifter system including: a series of semiconductor switches each having a control electrode and first and second load electrodes; a capacitance connected in series between each control electrode and ground; an inductance connected in series between each second load electrode of one semiconductor switch and the first load electrode of the adjacent semiconductor switch in the series; and means for selectively applying a control signal to each said control electrode for switching the associated semiconductor switch between a first state in which it operates as a low pass filter and a second state in which it operates as a high pass filter to introduce a phase shift in a propagated signal.

Cascaded low pass/high pass filter phase shifter system

A non-reciprocal phase shifter including a transmission medium connected between first and second terminals and having a predetermined phase shift which is the same in each direction and an amplifier circuit connected between the first and second terminals for introducing its inherent phase shift in one direction and a phase shift in excess of its inherent phase shift in the other direction for establishing a non-reciprocal phase shift; and a circulator made from such a phase shifter.

Non-ferrite non-reciprocal phase shifter and circulator

A distributed circuit includes a plurality of field effect transistors (FETS), each one of such FETS having gate, drain and source electrodes, with a first portion, or a first channel, of such FETS having gate electrodes and drain electrodes successively coupled between a first input terminal and an output terminal, and a second like portion or a second channel of such FETS having gate electrodes and drain electrodes successively coupled between a second input terminal and said output terminal. Separate bias circuits are provided to the input electrodes of the first and second channels. Bias signals fed to the bias circuits and coupled to the input electrodes place the FETS in an 'on' state to provide gain to r.f. input signals fed thereto, or in a 'pinch-off' state to isolate r.f. signals fed to the input electrodes of the FETS. Accordingly, a 2.times.1 switch or a two way active r.f. combiner which provides gain to a signal is provided.

Distributed amplifying switch/rf combiner

An internally matched power amplifier including an input terminal for receiving an input signal and an output terminal; a plurality of semiconductor devices connected with the load electrodes in series; transmission means for coupling the load electrodes of neighboring devices in the series and establishing an internal impedance match; the last device in the series having its other electrode connected to the output terminal; the first device in the series having its control electrode connected to the input terminal and its other load electrode connected to a common conductor and having a predetermined d.c. bias level and a predetermined signal voltage level between its control and its other electrode; first means for setting the control means of each device but the first in the series to the predetermined signal voltage level and second means for biasing the control electrode of each device but the first in the series to the predetermined d.c. bias level.

Internally matched power amplifier

A network is provided which is selectively configurable as a high pass and low pass filter. A pair of sets of field effect transistors FETS is provided, each set comprising three FETS connected in a T-configuration. A pair of the FETS in each set have a drain electrode of one FET coupled to the source electrode of the other FET to provide a series element of the T-configured set. The third FET has drain and source electrodes coupled between the common connection of the pair of FETS and ground to form a shunt element of the T-configured set. The gate electrodes of the series elements of a first one of the sets of FETS and the shunt element of the other set of the FETS are each fed a common control voltage signal. A first one of the sets of FETS is capacitively coupled between the input and output terminals of the network, and the second one of the set of FETS is inductively coupled between the input and output terminals of the network. One of a pair of complementary control signals is fed to each one of the gate electrodes of the FETS, and in response to a first state of said pair of control signals, the network is configured to provide a low pass filter having a first predetermined phase shift characteristic as a function of frequency over a predetermined operating frequency range. In response to a second, different set of said control signals, the network is reconfigured to provide a high pass filter section having a second, different predetermined phase shift characteristic as a function of frequency range. The difference in phase characteristics of the network configured as a low pass filter and a high pass filter is provided to be substantially constant over the predetermined frequency range, thereby providing a single phase shift bit.

Passive phase shifter having switchable filter paths to provide

A distributed power amplifier includes a plurality of field effect transistors (FETS), each one of such FETS having gate, drain and source electrodes, such FETS having cascaded gate electrodes and cascaded drain electrodes successively coupled between an input terminal and an output terminal. The gate electrode of each one of the successively coupled FETS is coupled to the input terminal through a corresponding one of a plurality of capacitors, and a common bias source through one of a corresponding plurality of high impedance bias paths. Since the gate electrodes of each FET are coupled to the input terminal through a capacitor, the coupling capacitor in combination with the inherent capacitance of each FET provides a potential divider into each gate electrode. Therefore, the power fed to each gate electrode is selected by selecting the value of capacitance for the coupling capacitors. In an alternate embodiment, a pair of sets of such capacitively coupled FETS is provided with the drain electrodes of each set of such FETS being coupled to a common output r.f. transmission line.

Distributed power amplifier

A bidirectional switch for selectively switching a microwave frequency signal between one of two signal paths. The switch includes a pair of field effect transistors, and a pair of transmission lines coupled together at one end thereof to provide a common port. Each second end of each microwave transmission line is coupled to a drain electrode of one of such field effect transistors to provide a branch port at each second end of each microwave transmission line. The electrical lengths of each transmission line are selected in accordance with the operating wavelength of the circuit to provide an impedance corresponding to an open circuit at one end, when a short circuit is provided at the opposite end. A signal is coupled between the common port and a selected one of the branch ports, in response to a pair of complementary binary control signals fed to the gate electrodes of the FETs. The control signals are used to select between one of the two signal paths by placing the FET having the drain electrode coupled to a selected branch port in a nonconducting state, and by placing the FET having the drain electrode coupled to an unselected branch port in a conducting state.

Bidirectional switch

A distributed amplifier having a plurality of successively coupled field effect transistors with cascaded gate electrodes and cascaded drain electrodes. A first one of such transistors has the gate electrode thereof coupled to an input terminal adapted to receive an input radio frequency signal and the drain electrode thereof coupled to a dc drain electrode bias circuit. The last one of the successively coupled field effect transistors has the gate electrode thereof coupled to a dc gate electrode bias circuit and a drain electrode coupled to a radio frequency output terminal which produces an amplified radio frequency signal. The source electrodes of the plurality of transistors are coupled to ground. A drain bias voltage source is coupled between ground and the drain electrode bias circuit, such bias circuit providing a direct current path between such drain bias voltage source and the drain electrodes of the transistors. The drain electrode dc bias circuit has a complex impedance with the real component thereof being provided, in part, by a resistor in such bias circuit. The resistor is coupled in series with a grounded high frequency by-pass capacitor and, hence, is not in the direct current path between the drain bias voltage source and the drain electrodes, but rather is in the radio frequency signal path to ground. With such arrangement, only a relatively small amount of dc power is dissipated by the resistor in such drain biasing circuit.

Distributed amplifier

A radio frequency network is provided having a plurality of field effect transistor cells, each one of such cells having a reactive element, and coupling means for electrically interconnecting the plurality of field effect transistor cells, such coupling means having an impedance in accordance with the reactance of the reactive elements of the cells to provide such radio frequency network with a predetermined characteristic impedance related to the impedance of an input circuit which feeds radio frequency energy to an input one of the plurality of cells. With such arrangement the coupling means and the plurality of field effect transistor cells provide the radio frequency network with a predetermined characteristic impedance which is related to the impedance of the input circuit.

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Lexington, MA, United States of America

Yalcin Ayasli