Abstract: A method of designing a linear rf amplifier comprising an output load impedance and an active device including the steps of (a) applying DC bias to the device, (b) applying two different frequency signals of an amplitude C, and (c) changing the value of the load impedance and recording the impedance value and associated C/I ratio for each impedance value (C/I being the ratio of amplitude C and amplitude I--the amplitude of an intermodulation product frequency). The last step (c) is repeated for a plurality of output levels. The above is repeated for a plurality of input power levels. The next step is selecting from the recorded information the impedance values corresponding to the maximum C/I ratio and recording the impedance values and corresponding C/I ratios, input power levels and output power levels. Then, choosing a desired C/I ratio from those recorded in the previous step and selecting the impedance value corresponding to the maximum output power level.

Abstract: An improved electronic velocity measurement device for an accessing type disk drive combines a differentiated cyclically discontinuous displacement (position error) signal (PES) with integrated motor current signals to produce an accurate continuous velocity signal over the entire range of displacements of a linear actuator. Differentiation of the displacement signal is achieved by low bandwidth differentiator circuitry that is corrected for periodic reversal of the displacement signal by a unique fill-in signal derived from integrated motor current. In a specific embodiment, the fill-in signal is derived by the use of a second differentiator using a second displacement signal in space quadrature with the primary displacement signal.

Abstract: A spin resonance spectrometer having a sample vessel 83 for containing substances to be examined. Pipes 92, 93 for the supply and discharge of test substances and possibly rinsing media are connected to the sample vessel, the pipe serving for supplying substances being connected to the sample vessel 83 such that the direction of movement of the substance supplied, on entering the sample vessel 83, has a component directed tangentially with respect to the sample vessel. As a result the supplied substance rotates in the sample vessel. The supply pipe 92, 93 may open substantially tangentially into the sample vessel 83, or a connecting member 184 comprising at least approximately helical channels may be located between the pipe 192 and the sample vessel 183.

Abstract: In a method of investigating the electrical resistivity of the ground, five electrodes are implanted in the ground at equal spacings along a straight line. An electrical current is passed through the ground between one pair of these electrodes and the potential difference between a further pair of the electrodes is measured. The electrode which is not used in this measurement is at one end of the line. A further measurement is then made with the four electrodes which exclude the electrode at the opposite end of the line. The measurements are combined to provide a measurement of apparent resistivity which is almost unaffected by a local resistivity variation.

Abstract: A frequency synthesizing system for use in an AM.multidot.SSB transceiver of double conversion type comprising a single crystal oscillator in its PLL synthesizer. The fundamental frequency of the PLL synthesizer provided by the oscillation of the crystal oscillator is selected to be n times (where n is an even number) the second intermediate frequency of the transceiver so that all the frequencies required for the operation of the AM.multidot.SSB transceiver can be derived from the oscillation frequency of the single crystal oscillator, whereby to simplify the structure of the AM.multidot.SSB transceiver and to facilitate the adjustment of the transceiver.

Abstract: An apparatus and method for extending the frequency range of a synthesizer r signal generator upward by several orders of multiplication. The basic stability of the synthesizer or generator is maintained at the higher frequency output. The output band of frequencies from a frequency synthesizer is processed through a homodyne multiplier and multiplied. The multiplied output is coupled to a power divider. The divider output is coupled to bandpass filters allowing selection of harmonic multiples from overlapping frequency bands to be made. A low pass filter in the circuit allows reduction in harmonics and higher order frequencies.

Abstract: A system comprising a demodulator for demodulating an input FM signal which has been subjected to interference by another FM signal, an envelope detector for detecting the envelope of fluctuation of the amplitude of the input signal, an AGC circuit for controlling the level of the input signal supplied to the envelope detector, a capacitor for passing only the AC component of the output of the envelope detector, a first delay circuit for delaying the AC component by a specific delay time, a circuit having a transfer characteristic of a hyperbolic function and converting the waveform of the output of the first delay circuit, an analog multiplier supplied at its x input terminal with the output of the waveform converting circuit and producing a distortion cancellation signal, a second delay circuit for delaying the output demodulated signal of the demodulator by the specific delay time, a first operation circuit supplied with the output signal of the second delay circuit and with the distortion cancellation sig

Abstract: A second order section of an electronic filter comprises three cascaded amplifier stages and a compensating amplifier stage coupled between the first and second amplifier stages. The compensating stage introduces a leading phase shift at high frequencies so that the normalized transfer function of the circuit, for different frequencies, is substantially identical.

Abstract: A delayed AGC circuit in which an AGC detection output is divided into two portions, one of them is applied through buffer means to an IF amplification stage to thereby control the gain thereof, and the other portion is applied to a tuner through a threshold circuit to thereby control the gain thereof. A variable resistor or potentiometer for AGC delay adjustment and a high-frequency bypass device are connected at a point in the AGC signal path from the output of the buffer means to the IF amplification stage.

Abstract: A bias circuit for a linear amplifier having an NF amplifier whose NF loop includes a first capacitor, bias means for providing a given bias potential to the amplifier through a charging circuit of a second capacitor and precharge means for precharging the first capacitor only when the second capacitor is charged by the given bias potential. With such a circuit connection, the first capacitor is charged within a short period from the time when the power source has been in ON state.

Abstract: A phase-locked loop oscillator system includes a phase comparator in the form of a flip flop which is switched between states in response to received data pulses at one input and oscillator generated clocking pulses at another input. The positive and negative outputs of the flip-flop energize positive and negative constant current generators whose outputs feed in parallel a low pass filter or integrator including a capacitor which is initially discharged at the start of data reception by a field effect transistor connected in parallel with the capacitor. The output of the filter is a voltage whose amplitude is a measure of the phase difference between the sets of pulses. This voltage controls the amplitude of charging current fed to a sawtooth waveform generator to control the frequency thereof. The output of the generator is processed to form the clocking pulses for the system.

Abstract: The output of a VCO, a referenced frequency signal and an offset frequency signal are mixed to provide a control signal for the VCO and a double offset frequency signal which is mixed with an output of the offset frequency source to provide a DC component having a positive polarity if the signals are inphase and the VCO is locked on one sideband and a negative polarity if the signals are out of phase and the VCO is locked on the other sideband. A sweep signal is activated and applied to the VCO in response to the VCO being locked onto the wrong sideband.

Abstract: A frequency generator provides a number of selectable predetermined spot frequencies to a high degree of accuracy in an economical manner. The output from a phase lock loop having a variable frequency divider is divided by a further variable frequency divider. The two dividers are controlled by pairs of divisor values held in a store.

Abstract: Disclosed is a spatially coherent semiconductor injection laser array. The system comprises a plural element laser diode array placed symmetrical in respect to an optical axis. An external resonating cavity formed of spherical lenses and plane mirrors is disposed about the array with its axis of symmetry coincident with the optical axis. A spatial filter in the Fourier plane of the laser diode array selects the TEM.sub.00 mode generated from each of the elements in the array. In operation, the system generates spatially coherent radiation from each of the elements of the array. The radiations are coherently coupled between all of the elements to provide a high optical power output in a spatially coherent beam.

Abstract: The invention provides a magneto-optical phase-modulating device employing either the transverse Kerr magneto-optic effect or the Faraday magneto-optic effect and embodying a magneto-optic layer (1) of a ferromagnetic or ferrimagnetic garnet type material which gives rise to an improved performance over known devices. Examples of the garnet type material which may be employed are a bismuth doped garnet, praseodymium and a garnet type material of the group known as orthoferrite materials.The invention finds particular application in laser gyroscopes.

Abstract: A tunable millimeter wave frequency Gunn oscillator operates efficiently beyond the normal Gunn oscillator frequency range through the use of a second harmonic enhancement circuit. The enhancement circuit is tuned to the fundamental frequency of the oscillator and is tracked with a second harmonic circuit to provide a wide tuning range. Lumped element circuitry is used to aid in providing the wide tuning range and to facilitate adjustment and fabrication.

Abstract: A circuit for quickly discharging a timing capacitor which is connected between the collector of a first transistor and the base of a second transistor, and which is charged via a current source connected to the collector of the first transistor. The circuit includes a third transistor whose conduction path is connected across the capacitor and whose control electrode is connected to the emitter of the first transistor. A turn-on current supplied to the base of the first transistor causes the timing capacitor to be discharged by a current whose amplitude is approximately equal to the turn-on current multiplied by the product of the forward current gains of the first and third transistors.

Abstract: A circulator comprises a cylindrical conductor housing, a disc shaped magnetic component mounted in said housing, three V-shaped inner conductors having two linear arms provided on the surface of said magnetic component, said inner conductors conjoining substantially at the center of said surface maintaining a 120-degree angle to each other, the open end of said V-shaped inner conductor being connected to the housing, and the other end of said V-shaped inner conductor being connected to an external strip line.

Abstract: This invention relates to an integrated filter circuit with a charge transfer device transversal filter and a further low-pass filter pre-connected to the transversal filter. The pre-connected filter includes a first capacitor and a second, significantly smaller capacitor, as well as two alternately actuable electronic switches.

Abstract: A two-pole inductorless monolithic crystal filter device comprising first and second spaced electrodes mounted on one face of the device, third and fourth spaced electrodes mounted on the opposite face of the device in superimposed relationship with the first and second electrodes, a first capacitor coupled between the first and fourth electrodes, means electrically coupling the second and third electrodes, and a second capacitor coupling the second and third electrodes to a point of reference potential with the first electrode and point of reference potential being designated as input terminals and the fourth electrode and point of reference potential being designated as output terminals.

Abstract: Multiple coupled high Q cavities are used to generate odd order elliptic function band-pass filters using a minimum number of cavities connected by simple and resonant coupling elements. A specific embodiment of a 3-pole, 20 MHz band-pass wave guide cavity filter centered at 3890 MHz is disclosed. Couplings between cavities may be either on the end walls or the side walls. The simple coupling elements may be simple coupling holes, and the resonant coupling elements may be a non-shorting screw in a window between cavities.

Abstract: A removable diode package for mounting beam-lead diodes in coaxial, stripline or waveguide microwave circuits is described. The diode package is capable of operation at frequencies above 40 GHz. A low-dielectric polyimide insulating washer is used to reduce parasitic elements normally associated with diode packages at microwave and millimeter frequencies.

Abstract: A multipole circuit breaker having a single contact operating mechanism for all poles and a fault current sensing means for automatic tripping of the breaker is provided with alarm switch means to indicate when opening of the circuit breaker has been caused by a fault condition. The operating mechanism includes a metal frame to which a latchable cradle is pivotally mounted. The frame includes parallel guide slots through which a formed pin actuator extends to be moved by the cradle as it operates between its latched and released (tripped) positions. A spring connected between the mechanism frame and the pin actuator biases the latter toward the cradle. An insulating extension element is adjustably mounted on the actuator to transmit motion of the latter to operate a switch in an alarm circuit, in accordance with cradle position.

Abstract: Both undervoltage and shunt trip auxiliary feature modules, adapted to be mounted side-by-side with one or more circuit breaker modules include an electromagnetic trip device having a trip actuator which is biased toward tripping position and is normally latched in a reset position. A lost motion connection interconnects the actuator with a trip member which is in direct driving engagement with the releasable latch for the automatic trip means of the circuit breaker so that when the actuator is released, movement thereof is transmitted through the trip member to the circuit breaker latch for tripping of the latter. Each auxiliary feature module also includes a reset member which acts to automatically reset the actuator after each tripping operation thereof. The reset member is in direct driving engagement with the cradle of the circuit breaker contact operating mechanism so that movement of the cradle towards its tripped position will operate the reset member in a direction to reset the actuator.

Abstract: A latching relay employing an electro-magnetic relay coil having associated therewith opposite end armatures. This relay coil receives operating power by way of an input contact member. One of the armatures carries a manually operated switch which also includes an end for actuating the closure contact. The opposite armature functions to assist in the manual switching and in its inactive state blocks operation of the primary armature. Another contact is associated with one of the armatures for providing high power transfer.

Abstract: A deflection yoke for use with a picture tube of a television receiver. A vertical deflection coil of the deflection coil has a larger winding angle on an electron gun side thereof than on a screen side thereof. A magnetic material piece is disposed inside the vertical deflection coil so that a vertical deflection magnetic field is formed into a strong barrel magnetic field on the electron gun side. As a result, a raster scanned on a faceplate of the picture tube is free from misconvergence and pincushion distortion. A core of the deflection yoke has sawtooth-shaped end surfaces, or auxiliary rings having sawtooth-shaped end surfaces are disposed on the end surfaces of the core. As a result, a wire of the vertical deflection coil is prevented from slipping on the end surfaces of the core although the wire of the vertical deflection coil is wound at a large winding angle on the electron gun side.

Abstract: A temperature-responsive electrical switch is provided which has a pair of axial leads, one of which is connected to the cylindrically-shaped electrically conductive housing, and the other of which passes through an insulator into the interior of the housing. A cylindrical-shaped, slideable electrical contact which is open at one end is positioned in the housing. A coil spring is located inside the slideable contact between the bottom end of the contact and an enlarged section of the insulator. The contact has a plurality of spring fingers which are integrally formed from the bottom of the contact and which project upwardly from the bottom of the contact toward the head of the insulated lead. A thermally-sensitive pellet, which melts at a predetermined temperature and is formed to have a cavity in it, is positioned below the spring fingers. The pellet is dimensioned transversely so as to force the fingers into contact with the head of the insulated lead.

Abstract: A coil form or body for coils is disclosed particularly for use in printed circuits. The coil form has a flange provided with insertable perforations in order to accommodate one-piece soldering lugs having soldering lug legs aligned at a right angle relative to one another in order to solder the coil wires and particularly for soldering into the printed circuit. The soldering lugs are equipped with at least one clamping element which abuts against the surface of the coil member flange when the soldering lug is pushed in and secures the coil form from shifting. The perforations are designed at a right angle and at least one latch is arranged on at least one soldering lug leg. This latch abuts against the exterior side of the flange when the soldering lug is inserted into the perforation.

Abstract: A laminated electric safety fuse which is built up laminated design consisting of various conductive materials which are embedded on an electrically insulating supporting member. The supporting member comprises one or more layers of electrically insulating material, a predominant part of which is a material having good thermal conductivity.In this design a narrowing effect is obtained which is up to 10 times larger than in known fuses, without sacrificing the current-carrying capacity of the non-narrowed parts of the fuse element.The various layers from which the safety fuse is built up can consist of materials with different electric conductivity, providing a new variable for obtaining an increased narrowing effect. The individual layers can be built up as films, e.g. by evaporative deposition.

Abstract: A method of assembling a normally-closed ambient thermally actuated switch comprises assembling into the open end of a casing a sandwich of elements including a meltable pellet, one or more springs, a backing member and a contact arm-deforming member which is released for movement under pressure of one of the springs when the pellet is melted at a given ambient control temperature. A power lead having resilient outwardly inclining contact arms at the inner end thereof and an axially outwardly facing shoulder is positioned in the casing so that the outer sides of the arms engage the backing member and the inner sides of the arms are confronted by the contact arm-deforming member.

Abstract: A component to be attached to a substrate or plate or other element including a hollow bushing having an extension for mounting directly to such other element. The extension is provided with a radially compressible shoulder portion engageable upon insertion into an aperture and a rod-like member to be seated firmly in the hollow bushing to prevent the relaxation and flexure of said bushing. In a preferred embodiment the rod-like member may be integrally molded with the component to be attached.

Abstract: An apparatus for diagnosing a malfunction of an electronic control system including sensors for electrically sensing conditions of sensing points of a vehicle and an electronic calculation unit for determining an energizing condition of an actuator for controlling a vehicle operation in accordance with output signals from the sensors is disclosed. The malfunction diagnosing apparatus is inserted intermediate of wires which connect the sensors or the actuator and the electronic control system, and when a voltage or current level on any wire assumes a non-steady state, the malfunction diagnosing apparatus determines that a malfunction has occurred at a portion associated with that wire and memorizes and holds the occurrence of the malfunction.

Abstract: A device for detecting and indicating low pressure or excessive heat in a pneumatic tire. A piezoelectric crystal is operatively associated with a temperature expansible member which expands in response to elevated temperatures. The combined dimensions of the piezoelectric crystal and the expansible member are selected so that one surface of the expansible member is a predetermined distance from the inside surface of the tire. Elevated temperatures cause the expansible member to expand and contact the interior surface of the pneumatic tire resulting in the compression of the piezoelectric crystal and the generation of an output signal. Additionally, deflation of the pneumatic tire causes the tire to deflect so that the predetermined spacing between the interior of the tire and the expansible pellet is reduced and the pellet contacts the inside surface of the tire resulting in the generation of an output signal. The output signal is used to actuate a spark gap to warn of an unsafe tire condition.

Abstract: Finger prints of authorized personnel are initially stored in digital form in a memory. Subsequently, personal identification is obtained by matching the fingerprints of individuals with the stored prints. The individual places his finger in an activator which indexes the finger and turns on the equipment. The fingerprint image may be refleted directly into an electronic image sensor or it may be initially impressed upon a tape for later image scanning. In either case, the electronic image sensor scans the fingerprint image and converts the optical characteristic of the print into a plurality of picture elements, and provides an electrical signal representative of each of the picture elements at its output. The picture elements are converted either in the electronic image sensor or in an analog to digital converter into a digital code representative of each picture element. These digital codes are entered into a temporary storage for comparison with the fingerprints contained in the memory.

Abstract: A circuit for monitoring digital data comprises a shift register for receiving the data to be monitored, the outputs of the shift register being fed either directly to the inputs of memory devices or via controllable gates. The memories are programmed to detect the number of logical `ones` present in the shift register, and the detected number is compared with a reference to determine whether the data should be accepted or rejected. In one mode of operation, the controllable gates alter the inputs to the memories such that they are all the same when the correct data is in the shift register. In another mode of operation, the gates supply the memories with unaltered data and the circuit can detect errors because the data is coded in such a manner that each block of data should contain the same number of digits and the same number of logical `ones`.

Abstract: An optical wand for automatically recognizing characters in a plurality of fonts incorporates a manually movable scanner incorporating a light source and a sensor array composed of a diode matrix. A first preprocessing unit is connected to receive the output from the scanner, and includes a correlation unit for buffering the data and apparatus for eliminating the effect of different characteristics of the individual photo diodes. The first preprocessing unit also includes a row tracking circuit and a segmentation circuit for presegmenting and for centering the character. Further segmentation, and filtering of the image is carried out by a second preprocessing unit which is decoupled from the first preprocessing unit, so that its operation is concurrent with that of the scanner. A recognition unit, decoupled from the second preprocessing unit, is connected thereto, and establishes individual values for the scanned characters by use of a quadratic polynomial classifier.

Abstract: A system for digitally quantizing, at high resolution, relatively small vations of an analog input signal. Initially, a reference level signal having a preselected value close to the average magnitude of the analog signal being quantized is compared with the analog input signal. The difference between these two signals is amplified and then analog to digital converted. By an iterative process, the reference level is adjusted as necessary to closely track the gross magnitude level of the analog input signal. Analog to digital conversion is applied only to the small difference signal, thereby allowing quantization to occur with high resolution. The system automatically keeps track of gross signal excursions so that the magnitude of the quantized signals is also available to the user.

Abstract: A battery-powered fire alarm including a smoke detector circuit, a controllable horn circuit and a battery monitoring circuit. The smoke detector employs a pair of complementary field-effect transistor switches with gates respectively connected to an ionization chamber and a potentiometer of a Wheatstone bridge circuit connected across the battery. The field-effect transistors are biased off to minimize standby power consumption and are connected such that the threshold voltages thereof are offsetting to minimize supply voltage sensitivity of the detector. When the voltage from the ionization chamber assumes a value approximately equal to a preselected alarm voltage at the potentiometer, both field-effect transistors turn on to energize an alarm circuit to sound an alarm. Hysteresis circuitry is provided to ensure that the complementary switches, once turned on, will not turn off and thereby terminate the alarm until after the alarm condition has terminated.

Abstract: A system for use in combination with (for electrical attachment to) electronic gear having an audio amplifier and which includes alarm means for generating a theft signal which is broadcast through a transmitter or audio system thereof and internal coded disable means for disabling the alarm upon insertion into the system of a predetermined coincidence signal that is substantially unique for each individual unit protected.

Abstract: A moisture responsive switch is employed for controlling the operation of a fluid operated sprinkling system or the like. The moisture responsive switch provides adjustable time delay means to prevent sprinkler flutter due to intermittent rain fall. Switch recovery time delay means may be adjusted to simulate irrigation evaporation conditions of local geographical terrain. Signal alarm means are provided that signal during precipitation independently of sprinkler system control by the moisture responsive switch.

Abstract: A compressed dehydrated cellulose sponge wafer has conductive plates attached to opposing faces. A bridging conductor electrically connects the two plates together upon swelling of the wafer responsive to its contact with moisture. One edge of the sponge is treated with adhesive so as to form a hinge. The wafer opens like a book upon contact with moisture forcing the extending plates into contact.

Abstract: An apparatus and method for monitoring the operation of centrifugal cyclones. Sensing means is disposed in the underflow spray discharge of a cyclone and is connected to electronic sensing circuitry adapted to produce a signal or alarm response when the cyclone ceases to operate in a normal manner. In one embodiment the apparatus and method employs a plurality of cyclones connected to receive feed material from a common manifolding means. Abnormal functioning of one cyclone of the group is immediately indicated by visual or audible alarm means and thereafter its sensing means may be disabled to permit the sensing circuitry to continue to be effective for the remaining cyclones. Delay means is incorporated in the circuitry to prevent a response when the abnormal condition is of short duration. One form of sensing means employs a probe which extends into the normal underflow discharge spray. Another form employs a paddle and switch assembly, with the paddle extending into the normal discharge spray.

Abstract: A tool breakage detecting apparatus is provided with a preset counter to be preset with a predetermined value. The content of the counter is subtracted one by one each time either one of a tool and a workpiece to be machined is moved a unit distance toward the other thereof from a cutting movement start position being spaced a predetermined distance from the other thereof. If the content of the counter is reduced an amount corresponding to a distance larger than the predetermined distance, tool breakage is detected.

Abstract: A pattern generation display system has a pattern code processing means, a refresh memory, a pattern generator and a pattern data processor. A pattern position on the raster scan display is defined by a base position datum and a displacement datum. The pattern code processor can calculate both of the position data as the address data for an effective operation. The refresh memory stores the code of a pattern and the displacement datum thereof at the address corresponding to the base position datum thereof. The pattern data processor completes the display of the pattern at the position deviated from the base position by the displacement datum. Such a system can easily shift the pattern generated by the pattern generator on the display screen by a small pitch. Therefore, it is easy to adjust the position of characters corresponding to the character or sentence features.

Abstract: A driving circuit for an electrochromic display cell wherein writing and erasing of electrode-segments are effected by relatively high write and erase transition potentials. After a predetermined transition period, the written and erased electrode-segments are stabilized at a desired coloration or transparency, respectively, by application of a maintaining write potential and a maintaining erase potential. The maintaining potentials are at a lower level than the respective transition potentials. In this manner, the write and erase charges or potentials on the electrode-segments are substantially maintained at a desired level to maintain the desired contrast ratio between the written and erased electrode-segment.

Abstract: A process for correcting data from a bistatic synthetic aperture radar to eliminate distortions and resolution limitations due to the relative positions and motions of the radar transmitter and receiver with respect to a target.

Abstract: An improved direction finding apparatus for determining the azimuth of a target source of radio frequency signals using in an optimal manner the signals from a central antenna and an associated array of direction finding antennas. The signals of the antennas are repeatedly scanned to generate running averages of the inphase and quadrature phase components of the RF phasors and to thereby reduce the effect of system noise on the measurement of the phasors. A series of computed candidate phasors corresponding to candidate target sources are then compared to the measured phasors and the azimuth of the candidate target having phasors most closely approximating the measured phasors is an optimal determination of the unknown azimuth of the actual target.

Abstract: Data signals are transmitted from a transmission unit (12) through a hybrid coil (16) and transmission line (18) to a remote transceiver. Data signals of a different frequency are received from the remote transceiver through the transmission line (18) and hybrid coil (16) in a full duplex mode and passed to a reception unit (26). A ratio of the signal levels of the received data signals passed through the hybrid coil (16) in a desired manner to transmitted data signals which leak through the hybrid coil (16) in an undesired manner is sensed at a reception signal output of the hybrid coil (16). The resistance of a variable resistance pad (17) provided in the transmission line (18) is varied in accordance with the sensed ratio so as to adjust the ratio to a predetermined optimum value. The sensed ratio is a predetermined function of the impedance of the transmission line (18) as viewed from the hybrid coil (16).

Abstract: A rectangular waveguide housing and a waveguide radiator have coaxial cavities that are contiguous. A pair of perpendicular walls intersect substantially on the axis of the housing to form therein four similar rectangular subwaveguides that may be excited to propagate electromagnetic waves in a TE.sub.10 mode. The walls have edges that are in the boundary between the contiguous cavities. A pair of intersecting tabs extend from the edges into the radiator. Additionally, a protrusion extends within the radiator from the intersection of the tabs. The polarities of the waves in the subwaveguides are selected to cause an electromagnetic wave to propagate through the radiator in either of two orthogonal difference modes or a sum mode that has desired beam shaping properties. The protrusion causes one of the difference modes to have a desired polarization.

Abstract: The present invention relates to a hybrid mode waveguide or feedhorn antenna for transforming the TE.sub.11 mode into the HE.sub.11 mode. The waveguide or antenna comprises a first waveguide section of uniform cross-section at the TE.sub.11 mode entrance port which in the antenna arrangement changes to a second section which flares outward toward the antenna mouth, and a spiro-helical projection bonded with a dielectric layer to the inner surface of the waveguide or antenna. The spiro-helical projection comprises a closely spaced helically wound wire structure formed of dielectrically coated wires which in the first section decrease in gauge size in small adjacent portions thereof as the helix progresses away from the TE.sub.11 mode entrance port and in the remainder of the helical projection, the same or decreasing gauge wire in adjacent portions can be used.