Mitsubishi Denki Kabushiki Kaisha

Kokusai Denshin Denwa Co., Ltd.

Mitsubishi Denki Kabushiki

Fumio Takeda

Tadashi Takagi

Kiyoharu Seino

Osami Ishida

Shinichi Sato

Yukio Ikeda

Takashi Katagi

Makoto Matsunaga

Katsuhiko Aoki

Yoji Isota

Tsutomu Hashimoto

Yoshitada Iyama

Matsuichi Yamada

Motoo Mizusawa

Yoshihiko Yoshikawa

Fumio Itoh

Keigo Komuro

Yoji Isoda

Yoshihiro Takeichi

Toshio Satoh

A distributed FET amplifier comprising an array of FET elements each having a gate terminal, a drain terminal and a source terminal. The gate terminals of the adjacent FET elements are connected by a first inductor, and the drain terminals of the adjacent FET elements are connected by a second inductor. Between the source terminals of each of the FET elements and the ground is connected a parallel circuit comprising a capacitor having a capacitance greater than the gate-source capacitance of the FET element and an impedance element connected in parallel to the capacitor for grounding the direct current. A bias voltage supply circuit for supplying a bias voltage to such as distributed amplifier is also disclosed.

Distributed fet amplifier and bias voltage supply circuit therefor

Between a circular conductor plate and a grounding conductor plate, lumped constant elements such as coils and capacitors are connected. As a result, the resonance frequency of an antenna can be changed in a wide range.

Antenna with lumped reactive matching elements between radiator and

A microwave power combining FET amplifier includes T-type input and output branch circuits 13, 14 for power splitting and combining, and interstage matching circuits 6a, 6b laterally connected at their mid-points a, b by a resistance circuit 15 which absorbs odd propagation mode waves reflected back from the output combiner due to non-uniformities between the post-stage FETs 4a, 4b.

Microwave power combining FET amplifier

A microwave semiconductor switch wherein first and second field effect transistors and first, second and third input/output microstrip lines are integrally formed on a semiconductor substrate. The first field effect transistor is connected in series between the second input/output line and a junction point of the first, second and third input/output lines at a position adjacent to the junction point. The second field effect transistor is connected at a second position spaced approximately a quarter of the wavelength from the junction point between the second position and the ground. The drain electrodes and source electrodes of the first and second transistors are placed at the same potential. The transmission paths for microwaves are switched by varying a bias voltage applied to the gate electrodes of the field effect transistors.

Microwave semiconductor switch

A power distribution circuit having two Wilkinson type bi-distribution circuits each of which halves and then distributes its input and formed of a microstrip on a dielectric substrate or a semiconductor substrate. The input terminals of the two Wilkinson type bi-distribution circuits are connected, while substantially middle parts of resistances used as isolation resistances of the respective Wilkinson type bi-distribution circuits are connected by a metallic thin wire.

Power distribution circuit having center portions of isolation resistors

A directional coupler having a main line and an auxiliary line each formed within a groove formed in a dielectric plate, having good directivity and capable of tight coupling.

Directional coupler

A crossed waveguide type polarization separator comprises a crossed waveguide for propagating orthogonal linear polarized waves, at least one conductor septum fitted in the crossed waveguide to totally reflect only one polarized wave in the linear polarized waves, at least one subwaveguide for receiving one linear polarized wave formed by the total reflection of the conductor septum, and a waveguide for receiving the other linear polarized wave which is not reflected by the conductor septum.

Crossed waveguide type polarization separator

An multi-frequency antenna feed system has a corrugated conical horn and a diplexer interconnected serially to be operative in two frequency bands represented by frequencies f.sub.H and f.sub.L corresponding to wavelengths .lambda..sub.H and .lambda..sub.L respectively, where 2f.sub.L .ltoreq.f.sub.H. Corrugated grooves on the inner surface of the conical horn have the depth h, where .lambda..sub.L /4&lt;h&lt;.lambda..sub.L /2. The corrugated conical horn has the inside diameter at its reduced diameter end which is not less than 2.6.lambda..sub.o, where .lambda..sub.o designates a wavelength at which the depth of the corrugated grooves ranges from three quarters of the wavelength and one complete wavelength.

Multiple frequency antenna feed system

Each of a transmitter and a receiver connected to an antenna through a duplexer includes a .pi./2 and a .pi. polarizer and an ortho-mode transducer (OMT) serially interconnected. In the receiver the OMT is connected at one output to a branching circuit and at the other output to a coupler which is connected to the branching circuit through a transfer circuit. In the transmitter, the OMT is connected at one input to a branching circuit and at the other input to a coupler subsequently connected to the branching circuit through a transfer circuit.

Antenna feed system

A branching filter for branching two microwaves from waves having two microwaves and a plurality of milliwaves includes two groups of coupling holes fluidically connected to one or more band-pass filters and a branching waveguide, one group of coupling holes being arranged on the wall of the conical horn so as to be equiangularly disposed thereabout with a 90.degree. interval defined between adjacent coupling holes when, for example, four coupling holes, filters, and waveguides are employed in such group, while the second group of coupling holes, disposed axially downstream of the first group of holes by means of a predetermined distance, is similarly disposed about the horn although angularly offset with respect to the holes of the first group through means of an angle of 45.degree..

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Kamakura, Japan

Fumio Takeda