Abstract: According to this invention, a monolithic integrated circuit device includes a semiconductor element, a metal ground film and a plurality of electrodes of the semiconductor element, first and second microstrip conductors, and a pair of via hole circuits. A semiconductor element is formed in a predetermined region on the first surface of a semi-insulating compound semiconductor substrate. A metal ground film and a plurality of electrodes of the semiconductor element are independently formed on the first surface of the semiconductor substrate. First and second microstrip conductors are formed on the second surface of the semiconductor substrate. A pair of via hole circuits connect the microstrip electrodes to input and output electrodes of the high-power semiconductor element, respectively.

Abstract: Apparatus and a method are disclosed for providing a microwave attenuator system using distributed (transmission line) reactive elements to achieve a reduction in the transmitted electrical signal amplitude. The attenuator system includes a fixed attenuator unit and an adjustable attenuator unit. The fixed attenuator unit contains a "T" resistive attenuator component. Transmission line resonator components are added to the attenuator component to provide frequency selectively. The transmission line resonator components are coupled to the resistive attenuator component in such a way as not to compromise the impedance match of the transmission line. The step adjustable loss component includes shunt transmission lines coupled to the center conductor of the transmission line by means of a spring contacting mechanism. The shunt transmission lines include preselected resistive elements.

Abstract: A high speed probe attenuator has an attenuator with a plurality of resistors connected in series between a probe input and an instrument output. A plurality of capacitors are coupled in parallel with pairs of the resistors in an interleaved fashion to spread the frequency correction along the attenuator. The output of the attenuator is coupled by a large diameter coaxial cable to a test instrument. The result is a high speed probe with no dribble-up effect and no overshoot.

Abstract: The invention is directed to an FSL in which a pair of planar ferrite members have planar surfaces in confronting relationship and at least one signal carrying conductor is supported between the ferrites and is closely coupled thereto. A magnetic biasing field is established having field lines disposed at an angle relative to the conductor such that the FSL has an increased attenuation at low frequencies resulting in a relatively flat limiting characteristic across the bandwidth. The conductor may lie in a plane parallel to the field lines or transverse to the field lines. In one embodiment the conductor zigzags in the plane of the field.

Abstract: A miniature, electrostatically actuated, dynamically tunable circuit which is operable to tune a transmission line in response to control signals. This circuit is micromachined with the use of integrated circuit processes such that a fixed transmission line is fabricated on a substrate and a movable signal line is fabricated over the substrate and is movable relative to the fixed transmission line in response to electrostatic fields produced when the control signals are selectively applied to an array of air bridge stator control electrodes which span the transmission line.

Abstract: A precision variable attenuator includes quadrature hybrid circuits, each having a first pair of isolated ports corresponding to the input and output ports of the attenuator. The second pair of isolated ports each are terminated with variable impedances in a manner to provide equal reflection coefficients at each port. Signals incident to the input port are coupled to the second pair of isolated ports and reflected therefrom to be coupled to the output port.

Abstract: A method for comparing the quality of RF absorbers uses a TEM cell which is provided with a low-reflection termination, in which cell the absorber wall (5) is equipped with reference absorbers (13). A steep-edged pulse wave is radiated in by means of a pulse generator (9) and a scattered wave reflected by the test absorber (14) is detected by means of a sensor (10). A reflection of the absorber wall is then determined by means of a first calibration measurement. The reference absorber is removed in a test area and a reflection of a metal wall (8) lying behind it is then determined by means of a second calibration measurement. Finally, a reflection of the test absorber (14) arranged in the test area is determined in a comparison measurement.

Abstract: A resistive film attenuator element comprised of a dielectric-mounted resistive film distributed ladder network having tuning stubs, combined in a coplanar structure, to provide a wide band attenuator having a substantially flat frequency response over a wide range of frequencies, for example, from D.C. to 40 GHz.

Abstract: An attenuator element has a reference path and a relative attenuation path. The reference path is formed by a T-network of two FETs operated in the passive mode and a shunt path and the attenuation path is formed with a similar structure, with the FETs in the shunt path having a different channel width. Instead of a T-network, a Pi-network of transistors can be used. The respective gates of the FETs along the reference path are connected to a first control input corresponding to either zero volts or the pinch-off voltage and the respective gates of the transistors on the attenuation path are connected to a complementary control input having a voltage corresponding to the other of zero volts and the pinch-off voltage. Another type of attenuator element is formed with a reference path having a transmission line and an attenuation path formed by a resistive T-network, with the attenuation and reference paths being alternately selectable by two single pole, double throw switches.

Abstract: A microwave attenuator is constructed on an insulative substrate which supports a resistive region, input/output electrodes and shunt electrodes. The shunt electrodes are preferably constructed using trapezoidally shaped portions on the face of the insulative substrate, on which the resistive region is formed, to increase the width of the electrodes. The shunt electrodes extend down to a ground plane on the face of the insulative substrate opposite the face on which the resistive region is formed. In one embodiment, the shunt electrodes form a wide strip on the outside of a rectangular substrate. In another embodiment, the shunt electrodes extend from the resistive region through holes positioned close to the resistive region.

Abstract: An electric noise absorber, comprising divided magnetic substances made of ferrite, a holding member for holding the magnetic substances at its holding projections, and engaging members formed in the magnetic substances which engage with the holding projections. The electric noise absorber is attached to and detached from an electric cable easily without removing the electric cable and is composed of a minimum number of units.

Abstract: An electric noise absorber, comprising divided magnetic substances made of ferrite, a holding member made of elastic material and fixtures for being connected to each other or fixed to a component of an electronic device, and engaging grooves formed on the outer surfaces of the magnetic substances for engaging with the holding member, is attached to and detached from an electric cable easily without removing the electric cable, and is composed of a minimum number of units.

Abstract: A monolithic device for controlling the transmission of RF energy. The device comprises doped regions selectively implanted along two lateral lines in a buffer layer disposed on a semi-insulating substrate. Two ground conductors are disposed on said doped region to form ohmic contacts therewith, and a signal conductor is disposed directly on the buffer layer between the two ground conductors to form a Schottky contact. The buffer layer is responsive to a DC potential applied between the signal and ground conductors for selectively attenuating RF energy transmitted through the device.

Abstract: A variable attenuation device intended to be inserted between a transmitter circuit having a certain internal impedance and a load circuit; it composed of at least on parallel attenuation branch made up from a variable resistance component (in particular a p-i-n diode) and a bias circuit to vary the resistance of the component as a function of an attenuation control variable. The parallel attenuation branch has a limiting component which is connected in series with the variable resistance component and whose value ensures the matching of the internal impedance of the transmitter circuit.

Abstract: A MMIC variable att4enuator uses depletion mode Schottky gate FETS as variable conductance devices in a ".pi." configuration to vary attenuation as a function of a DC control voltage. Attenuation is flat within .+-.1 dB, VSWR is .ltoreq.2:1 throughout the operating frequency and control voltage range, and about 12 dB variable attenuation is provided. The ".pi." is formed by FETs in shunt to ground between attenuator input and output, and by a FET in series between input and output. Resistors and an inductor connected in parallel with the series FET extend attenuator bandwidth to 20 GHZ and improve attenuation linearity versus control voltage. A resistor in series with each shunt FET also improves linearity. The typically 0 to +3 VDC control voltage is applied to the FET gates and drain/source leads permitting attenuation control with a single control voltage.

Abstract: Inductorless bias networks include a bias circuit having a bias return path which is coupled to and biases a variable impedance device in a relatively nonconductive state. Another bias circuit including a FET renders the variable impedance device relatively conductive in response to control signals so that one port is coupled to another port, for instance.

Abstract: A four-pole or three-pole structure adapted to propagate an electromagnetic wave, such as an electrical line or cable or electronic component, comprises a lossy non-linear dielectric material distributed in a wave propagation direction. This material has a non-linear conduction characteristic whereby it is substantially non-conductive at any rated applied voltage of the structure and substantially conductive at any abnormally high applied voltage. It consists of a polycrystaline material comprising thin interstitial layers procuring a tunneling or Schottky type effect in response to a high electric field resulting from such abnormally high applied voltages. It absorbs both voltage surges (varistor effect in the time domain) and high-speed transients (lowpass filter effect in the frequency domain). The structure can be used to provide protection against lightning strikes, nuclear electromagnetic pulses, electrostatic discharges and radio-frequency interference in general.

Abstract: A FET variable absorptive attenuator utilizes FETs as variable resistors controlled by voltages applied to their gate terminals, the FETs preferably being arranged in a T configuration with resistors connected in parallel with two series FETs, as well as a shunt FET in the form of a distributed shunt FET. One control voltage adjusts the resistances of the series FETs, and another controls the resistance of the distributed shunt FET. A proper combination of the two control voltages yields a desired level of attenuation with optimum input/output impedance matching. The resistors allow the series FETs to be biased well below their pinch-off voltages to minimize the parasitic capacitances of the series FETs at relatively high attenuation settings, improving the isolation for high attenuation settings at relatively high frequencies and also enabling the attenuator to function as a switch. They also improve the power-handling capability at high attenuation settings.

Abstract: This invention provides a switched limiter with variable attenuation designed with monolithic GaAs p-i-n diodes. Greater than 30 dB of small-signal variable attenuation is achieved at X band frequencies, with a minimum insertion loss of 0.5 dB. The variable attenuation switched limiter provides 15 dB of isolation to a +30 dBm input signal. Under bias conditions that result in variable attenuation the variable attenuation switched limiter input impedance remains matched. When used as a passive limiter, 7 dB of limiting has been achieved for a +30 dBm input signal at 10 GHz.

Abstract: Programmable attenuators including DPDT relays or pairs of SPDT relays with terminals which are interconnected through conductors and attenuator sections disposed on opposite sides of grounded isolation elements, and so configured and supported by printed circuit boards or the like as to provide very high isolation while obtaining flat response characteristics up to very high frequencies, in the megahertz range.

Abstract: A coaxial cable for coupling radio frequency (RF) signals therethrough with a predetermined, nominal attenuation comprising a center conductor selected to maintain the attenuation of the coaxial cable at substantially the nominal attenuation substantially independently of the frequency of the RF signals over a predetermined frequency range, such as from 2 to 18 GHz. In a preferred embodiment of the invention, the center conductor is selected having a nominal volume resisitivity (.rho.) and a nominal permeability (.mu.), with the volume resistivity-permeability product thereof substantially varying inversely with changes in frequency of RF signals coupled through the cable. With such arrangement, a lossy coaxial cable providing substantially constant attenuation over a broad range of frequencies, such as greater than three octaves, is provided having reduced size, complexity and VSWR from conventional lossy cable assemblies comprising a conventional coaxial cable coupled in series with an attenuator.

Abstract: A high performance, low cost variable attenuator is disclosed with minimal size and weight requirements. The variable microwave attenuator of the present invention includes a microwave stripline transmission line connecting the input and the output thereof; first and second ground planes are disposed on opposite sides of the transmission line; and a dielectric card having a metallization pattern is disposed on at least a portion thereof. The card is adapted for variable interposition between the transmission line and the first ground plane to provide variable attenuation of microwave energy. A specific teaching of the invention relates to the design of the metallization pattern to provide vernier attenuation.

Abstract: A pin diode variable attenuator featuring decouping values higher than those achievable using the technique used so far, is described. This result has been achieved by implementing the line sections which the pin diodes are connected to with a characteristic impedance different than the characteristic impedance input and output to/from the attenuator.

Abstract: A programmable microwave attenuator includes coax to slab line connectors which use rigid pin inner conductor captivation at an inner conductor interface surface within the confines of the coaxial outer conductor to improve mechanical reliability and reduce frequency dependent insertion losses. Narrow gaps between the edges of the slab line inner conductor and the coaxial outer conductor reduce unwanted modes of microwave energy transmission by concentrating the electric field at the edges of the slab line inner conductor before it emerges from the coaxial outer conductor into the slab line. A similar gap exists between the edges of the slab line inner conductor and the slab line outer conductor so that unwanted modes of microwave energy transfer are minimized after the outer conductor interface surface.

Abstract: The present invention relates to an attenuator for reducing noise and distortion, preferably in the audio frequency range. Briefly stated, the present invention is comprised of two wedge shapes in one block with two axially opposing leads connected to the wedge shape midway along the line formed by the intersection of two adjacent sides. The leads are preferably bent at 90.degree. and connected to attenuator conductive strips contained on a circuit board. The attenuator conductive strips on the circuit board are preferably at 90.degree. with respect to parallel conductive strips connected to a speaker or the like. The entire attenuator structure is preferably covered with an insulative or dielectric material.

Abstract: A microstrip attenuator comprising a block of lossy material which is preferably impregnated with ferrite particles and having a groove of a predetermined height and width dimension formed in the bottom surface thereof defining a tunnel and positionable upon a microstrip transmission line assembly, such that the microstrip element of the assembly passes through the tunnel, but is in non-contact relation with respect to the surface-mounted microstrip element. The degree of attenuation afforded by the attenuator is primarily a function of the aforementioned length and height dimension of the tunnel formed in the block of lossy material.

Abstract: To improve the bandwidth of a display driver stage in a wideband video signal processing and display system, the output of a display driver amplifier is coupled to a display device via a transmission line having an unterminated output end, a misterminated source end to develop a negative non-zero source reflection coefficient, and a phase delay within a given range.

Abstract: A high frequency coaxial switch has a coaxial connector mounted on a housing to provide electrical access to a cavity within the housing, the cavity being small to suppress moding. The coaxial connector is electrically connected to a microstrip conductor on a hybrid circuit board within the cavity, and switching is accomplished by compensated contact striplines which electrically make or break contact with the microstrip conductor.

Abstract: An attenuator device is disclosed defined by an inner member having an outer cylindrical surface and a coaxial and relatively rotatable outer member having an inner cylindrical surface. Longitudinally extending grooves are defined in the respective surface of each member. Attenuating structure is disposed in the longitudinal length of the grooves of one of the members while bowed leaf springs are disposed in the longitudinal length of the grooves of the other member. The bowed leaf springs extend from the grooves of the other member to engage the grooves and attenuating structure of the one member to thus provide both detenting and grounding for the attenuator device.

Abstract: An attenuator is in the form of a pad comprising a coating of resistive material which connects an input port, an output port and a pair of linked constant potential ports. The regions of the pad adjacent to the outer edges of the input port are provided with outwardly pointing cusps with curved boundary edges. These reduce current crowding at the edges of the input port, and avoid localized overheating of the adjacent regions of the pad, which could result in pad failure.

Abstract: A broad band, thin film attenuator for microwave circuits is constructed by placing a ground plane conductor on one side of a ceramic, insulating substrate, and conductive, resistive, and reactive elements on the other side of the substrate. Capacitive stubs are provided to compensate for inductance in grounding conductors between resistance elements and the ground plane conductor. Constrictions are provided in input and output conductors to provide increased series inductance to compensate for distributed capacitance of the resistance elements. One resistance element is constructed so that the interface between the input conductor and that resistance element forms an obtuse interior angle with an adjoining transitional edge extending from the input conductor to the grounding conductor, and the transitional edge forms an obtuse interior angle with the adjoining edge of the grounding conductor, so as to minimize current density concentrations and distributed capacitance.

Abstract: The present invention relates to a broadband variable attenuator comprising a two- or three-section transmission line with a separate PIN diode bridging each of the two gaps between the adjacent ends of the transmission line sections. The two PIN diodes are disposed in series opposition and the first, second and third transmission line sections are connected to a diode variable biasing source to cause (a) substantially a total reflection of an input signal to the attenuator for a bias below a first value, (b) substantially a total transmission of an input signal through the diodes for a bias above a second value, and (c) a selected amount of both partial reflection and partial transmission of an input signal for a bias value between the first and second values. The broadband variable attenuator can be implemented using microstrip, stripline or coaxial technology without the need of d-c isolation capacitors or applique resistors while providing a maximum insertion loss under zero bias conditions.

Abstract: A microwave attenuator forming two series connected L-pads is comprised of a plurality of electrically conductive, resistive, and non-conductive sections disposed on the surface of an elongate dielectric cylindrical base. The series resistances are connected through a conducting strip having an impedance that matches the impedance of the L-pads.

Abstract: A microwave coaxial switch has a central conductor which comprises two fixed segments connected by a movable segment, controlled by a switch member. The resilient ends of the fixed segments come into engagement with the contacts of a quadripole such as an attenuator cell, when they are freed from the movable segment, this latter having come into engagement with the ground conductor.

Abstract: Provided is a design for a terminated R.F./microwave Wheatstone bridge and a precision termination which can be used therewith.

Abstract: According to the invention, a microstrip microwave frequency attenuator comprises a distributed series resistance medium and distributed shunt resistance medium, wherein the shunt resistance medium is disposed parallel to the direction established for electric fields in the microstrip between the signal path and ground through the energy supporting medium. In the preferred embodiment, the series resistance path has a resistance value per unit length equal to about one-third of the resistance value per unit length compared to the shunt resistance path between the series resistance path and the ground plane.

Abstract: A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

Abstract: A high power, high frequency attenuator which provides attenuation steps ch are switchable at very high speed, the attenuator implementing a method by which the input signal is split into two separate signals which are then subjected to impedance mismatches in the signal path, so that a portion of the split signals are reflected back to the signal splitter for dissipation there and the remaining portions of the split signal are transmitted to a summing circuit for recombination and output. The value of mismatch imposed determines the degree of attenuation obtained. The splitting of the signal reduces the stress upon the mismatched components as well as permits high switching speeds of the mismatches in and out of the circuit. In one embodiment of the invention directional couplers are used to provide the signal splitting and recombination functions, with the result that high isolation is achieved between the input port and the reflected signal caused by the mismatches.

Abstract: A protection circuit for an electronic AC/DC instrument employs an input resistor connected across the DC input terminals of the instrument in series with the inner terminal of a coaxial cable connected to a resistance input probe, the inner cable being connected to the AC input terminals by means of a capacitor.

Abstract: A meander line slow wave structure mounted on ceramic bars for a microwave evice such as an injected beam crossed-field amplifier includes frequency selective attenuator means which will preferentially attenuate waves at frequencies near and within the stopband of the slow wave structure by the placement of side absorber bars of attenuating material adjacent to the outer side surfaces of a plurality of meander line finger segments. The frequency selective absorber material, in its preferred form, comprises a beryllia and silicon carbide ceramic composition which additionally adapted to accommodate metallic absorber top plates, nichrome films, and slotted side ring configurations.

Abstract: Conventional attenuators and matched loads for dissipating power at hyperfrequencies are uniform structures giving constant attenuation per unit length. This results in most power being dissipated at an input end. The present invention increases the maximum total power that such a resistance can dissipate by providing a non-uniform structure in which dissipation per unit length increases when going away from an input end, in such a manner that power is dissipated in a substantially uniform manner throughout the structure. A series resistance (3) between two parallel resistances (4 and 5) are in the shape of a sector of a circle.

Abstract: A self-contained switchable, incremental attenuator device for interposing in a two line power circuit to attenuate the power level for proper power matching. The device includes a series of modulized, individually switchable attenuator circuits of differing attenuation values mounted upon a pluggable card for interfacing with input and output connectors of a circuit. The attenuation values of the sections are selected such that manipulating the switches will allow attenuation of the power level in the circuit by an integral multiple of a given base incremental value within a given range. The attenuator device is designed to mate with a mounting device for holding the attenuator in contact with the circuit connectors.

Abstract: A digitally programmable attenuator for high speed and a large dynamic range is constructed with a phase-controlled attenuator for small steps of attenuation and an attenuator of switched resistive pads for larger steps. The attenuators are connected in tandem and actuated combinatorially with the phase-controlled attenuator being switched into operation for the small steps, and the resistive pads being switched into operation for the large steps. A phase-controlled attenuator is constructed to permit adjustment of the attenuator characteristic, and a switched-pad attenuator is constructed to be phase shiftless.

Abstract: A broadband attenuator section in a meander line slow wave structure is dlosed for attenuating signals reflected between the output and input of the slow wave structure. The attenuator section comprises a multi-element ceramic support structure intermediate the meander line conductor pattern and the substrate wherein the support elements are comprised of a beryllium oxide-silicon carbide ceramic composition with a taper in the percentage of silicon carbide being provided in the transition region from a loss free section of the slow wave structure to a lossy attenuator section. The taper in percentage involves the use of ceramic support elements arranged in a sequence of 1%, 2% and 5% silicon carbide composition prior to the main attenuator section which is comprised of 10% silicon carbide - 90% beryllium oxide support elements.

Abstract: A radar receiver protector having high isolation and low insertion losses due to a unique microwave assembly configuration is disclosed. The receiver protector includes at least one high power input protection stage and a sensitivity time controlled multi-level attenuation which together achieve rapid switching with a non-critical bias supply and circuit configuration and develop attenuation levels which are invariant with temperature and insensitive to diode parameters.

Abstract: A variable attenuator is formed by a section of lossy transmission line having a plurality of PIN diodes in parallel with discrete sections of the line. A D.C. current flowing through the transmission line controls the effective resistances of the diodes and thereby varies the per unit length resistance of the line.

Abstract: A pi pad attenuator for microwave systems is formed on an insulating substrate in the form of a small card or chip. Resist material covers the substrate, and input and output conductors are plated over the resist in the desired configuration. Resist material is removed to leave conductors interconnected in a predetermined pattern by individual sections of resist to form the pi pad. Characteristics of the attenuator are determined by the area of the remaining resist sections and/or the thickness of the applied resist.

Abstract: A programmable microwave card-type step attenuator is compensated for switch capacitance to render its attenuation response effectively insensitive to frequency over most of its dB range and comprises a plurality of cascaded attenuator sections disposed on a microstrip card with each attenuator section including a deposited film microstrip resistive network adapted to be switched into or out of the signal line by a miniature relay switch, a minimum loss transmission line being inserted into the signal line when the resistive network is switched out. Each of the microstrip resistive networks includes a reactive element connected thereto to compensate the frequency response of the resistive networks due to deviations from the optimum electrical length, thereby minimizing the frequency sensitivity of the attenuation characteristic of the section. Inductive effects are achieved by use of suitably shaped conductive areas or by removal of portions of the resistive networks.

Abstract: The planar transmission line attenuator and switch is formed on a flat piece of semiconductor material. Transmission line metallic conductors are deposited on a flat surface of the semiconductor material, and at least one of the metallic conductors forms a Schottky barrier contact to this flat semiconductor surface. The gap between the metallic conductors defines a shunt current path through the semiconductor material. The semiconductor material at the surface in contact with the transmission line conductor must be conductive. By applying a bias voltage to the metallic conductor forming the Schottky barrier contact, the conductivity of the shunt path can be controlled by changing the depletion layer width across the Schottky barrier. A plurality of planar transmission line switches can be combined into multi-port networks, examples of which are cross-bar switching devices and .beta. element switching devices.

Abstract: An attenuator and termination having a relatively flat frequency response r attenuating and dissipating electrical energy is comprised of a plurality of cascaded tee attenuator sections formed on a substantially flat surface ceramic substrate comprised of alumina, for example. The attenuator sections are configured from a single thin film series resistor comprised of gold and a plurality of shunt resistors formed from a layer of cermet which underlies the gold film resistor. The cermet shunt resistors extend away from the series resistor to the side edge of the substrate where they terminate in a ground contact configuration which wraps around the side and lower surface of the substrate.