Abstract: A receiving device is used that includes a main tuner 11, a sub-tuner 12, and a control unit 13 is used. The main tuner 11 and the sub-tune 12 have local oscillators 25, 45, respectively, for generating local oscillation signals according to frequencies of selected channels, and extract signals on the selected channels by using the local oscillation signals. The control unit 13 judges whether the frequency of the channel selected by the main tuner 11 is identical to the frequency of the channel selected by the sub-tuner 12. When it is judged that they are identical, the control unit 13 stops the generation of the local oscillation signal by the local oscillator 45 of the sub-tuner 12 and causes the sub-tuner 12 to extract the signal on the selected channel by using the local oscillation signal generated by the local oscillator 25 of the main tuner.

Abstract: Terminal equipment has mounted thereon a wireless module including a communication device having a transmission and reception antenna for connection to a wireless network and includes a first antenna unit which is connected to the transmission and reception antenna physically or spatially and a second antenna unit which is connected to the first antenna unit and transmits and receives radio signals directly to and from the wireless network such that not only communication quality is upgraded, but a radio signal reach distance between the terminal equipment and the wireless network is extended.

Abstract: A microwave oscillator for inducing parallel feedback from collector to base and obtaining a stabilized oscillation output is realized by connecting MSL A with released end to a base terminal of a transistor, connecting MSL B to its collector terminal, and disposing a DR closely to the MSL A and B to couple them electromagnetically. The length between the released end and the position of MSL A which is closest to the center of DR is set to ?g1/4 (?g1 is the guide wavelength in the MSL A), and HIL is merely connected to this position as a bias supply line to the base terminal. This structure does not require the choke circuits which occupied a relatively wide area on the conventional circuit board, and a small and stable microwave oscillator having excellent phase noise characteristics, and a low-noise converter for receiving satellite signal by using the same are realized.

Abstract: A terminal equipment is used by mounting thereon a wireless module including a communication device having a transmission and reception antenna for connection to a wireless network and includes a first antenna unit which is connected to the transmission and reception antenna physically or spatially and a second antenna unit which is connected to the first antenna unit and transmits and receives radio signals directly to and from the wireless network such that not only communication quality is upgraded but a radio signal reach distance between the terminal equipment and the wireless network is extended.

Abstract: A microwave oscillator for inducing parallel feedback from collector to base and obtaining a stabilized oscillation output is realized by connecting MSL A with released end to a base terminal of a transistor, connecting MSL B to its collector terminal, and disposing a DR closely to the MSL A and B to couple them electromagnetically. The length between the released end and the position of MSL A which is closest to the center of DR is set to &lgr;g¼ (&lgr;g1 is the guide wavelength in the MSL A), and HIL is merely connected to this position as a bias supply line to the base terminal. This structure does not require the choke circuits which occupied a relatively wide area on the conventional circuit board, and a small and stable microwave oscillator having excellent phase noise characteristics, and a low-noise converter for receiving satellite signal by using the same are realized.

Abstract: A microwave mixing circuitry has a plurality of microwave signal input terminals, a local oscillator for outputting a local oscillation signal for the purpose of generating an intermediate frequency signal from the microwave signal input by the microwave signal input terminals, and a plurality of field effect transistors (“FET”) for frequency converting. The FET gates are input with the microwave signal input from microwave signal input terminals. The FET drains are input with an output of the local oscillator. A plurality of gate voltage control circuitries control gate voltages of the FETs thereby causing one of the FETs to perform nonlinear operation while turning off another of FETs at the same time. An intermediate frequency signal output terminal outputs the intermediate frequency signal produced by the nonlinear operation of one of the FETs.

Abstract: An automatic microwave gain control device comprises a signal amplifier, a directional coupler coupled to one terminal of the signal amplifier for receiving a portion of an amplified microwave signal power, a microwave detection diode connected to one end of the directional coupler, a bias supply circuitry supplying an adjustable D.C. bias voltage to the microwave detection diode, a D.C. amplifier for amplifying a voltage derived from an addition of a microwave detection output voltage of the microwave detection diode and the bias voltage of the bias supply circuitry, and a variable attenuator provided at another side of the terminals of the signal amplifier, wherein the variable attenuator controls an output power outputted from an output terminal to be constant power by way of controlling a magnitude of attenuation of the signal at the another terminal of the signal amplifier according to an output voltage of the D.C. amplifier.

Abstract: A micro-wave mixing circuit produces producing a stable frequency conversion characteristic against a dispersion of output voltage of a local oscillation signal tapped off from a local oscillator. A micro-wave signal fed into a micro-wave signal input can be converted into an intermediate frequency signal of 1 GHz bandwidth where a stable frequency conversion characteristic is maintained against a dispersion of an output voltage of a local oscillation signal, by supplying bias current from a bias supply circuit to an anode of a Schotkky barrier diode responsive to a local oscillation output which is supplied from a local oscillator.

Abstract: An oscillator circuit including a metal plate secured to a dielectric substrate. A micro strip line is mounted on the dielectric substrate. One end of the micro strip line is connected to the gate terminal of a field effect transistor for microwave oscillation and the other end of the micro strip line is grounded to the metal plate via a terminal resistor. A dielectric resonator is secured with an ordinary adhesive to the inner wall of a shield case. Attaching the dielectric resonator to the shield case allows the degree of coupling, defined by the distance between the micro strip line and the dielectric resonator, to be freely set. A tuning screw is screwed through the metal plate and the dieletric substrate opposite to the dielectric resonator. The microwave oscillation circuit can be used with a down converter.

Abstract: A switchable microwave signal mixing circuit is disclosed which comprises: an osc 3 for generating an osc signal; 1st and 2nd microstrip lines 6, 7, coupled to the oscillator, for receiving 1st and 2nd microwave signals and the osc signal respectively; a bias voltage control circuit 54 for alternatively generating 1st and 2nd control bias voltages; 1st and 2nd FETs 8, 9, having 1st and 2nd gates supplied with the 1st and 2nd control bias voltages and coupled to the 1st and 2nd microstrip lines, drains supplied with bias voltages, and sources respectively, for alternatively generating 1st and 2nd IF signals from the 1st and 2nd microwave signals and the osc signal from the 1st and 2nd microstrip lines according to the control bias voltages; and an IF signal outputting circuit 14-18, 21 for outputting one of the IF signals selectively generated.

Abstract: A microwave mixing circuit of a small size for selecting a signal to be received out of plural microwave signal inputs, and converting it to an intermediate frequency signal, and a down converter comprising it are provided. A microwave input signal within a band of 12 GHz applied to one microwave signal input unit is guided through a bias terminal from a comparator into a mixer diode to which a bias current is supplied, and is converted in frequency by the mixer diode. A microwave input signal applied to other microwave signal input unit is guided through the bias terminal from the comparator into a mixer diode to which bias current is not supplied, and is hence not converted in frequency by the mixer diode. As a result, only an intermediate frequency signal of 1 GHz band corresponding to the former microwave signal appears at the intermediate frequency signal output terminal.

Abstract: A microwave oscillator includes a substrate having a circuit pattern on the top surface, a thin copper foil covering the bottom surface, and a hole. An electronic component is mounted to the top surface of the substrate. A metal plate is attached to the bottom surface of the substrate thereby closing the bottom of the hole. A dielectric resonator is attached to the metal plate through the hole. Since the dielectric resonator is attached to the metal plate by soldering, the bond between the dielectric resonator and the metal plate is stronger and more stable than that achieved by using a conventional adhesive. This enhances the reliability against temperature changes; mechanical impact or humidity.

Abstract: An electromagnetic radiation converter for receiving and converting microwave signals having a circular or linear polarization. The converter comprises a waveguide for transmitting both circularly and linearly polarized signals, and a first mode transducer for converting the vertical component of the microwave signal into a corresponding signal on a microstrip line, a second mode transducer for converting the horizontal component of the microwave signal into a corresponding signal on a microstrip line, and means for combining the outputs of the first and second transducers. When receiving a circularly polarized signal, the combination means adjusts the phase of the vertical and horizontal components of a circularly polarized signal such that the phase of the vertical and horizontal components are equal prior to being combined so as to produce a signal equivalent to the circularly polarized signal originally received.

Abstract: A waveguide-microstripline transformer comprises a waveguide which is closed at one end and has a slit at a side wall thereof, a dielectric substrate plate placed on the slit, a microstripline placed on the dielectric substrate plate, and a shield case covering the dielectric substrate plate, whereby less blocking of the incident electromagnetic wave is attained.

Abstract: A microminature down converter for satellite communications has a structure in which high frequency circuit printed boards (5) are respectively arranged on peripheral four surfaces of a box made of a die-casting and a power printed board (1) for supplying power to each of said high frequency circuit printed boards is disposed on a surface opposite to an input portion of a wave guide tube, whereby power supply to each of the high frequency circuit printed boards (5) is performed not through lead wires. Therefore, electromagnetic couplings occurring between printed boards are prevented and electromagnetic couplings between high frequency signals occurring in the printed boards and lead wires are also prevented, so that it is possible to restrain occurrence of undesired waves.

Abstract: A microwave circuit includes a concentric-circle-like prominence (7) formed on a contact surface which is on the side of a metal body (3) serving as an external conductor of a coaxial line and which connects a conductor strip (1) of an MSL formed on a dielectric substrate (2) to an internal conductor of the coaxial line through a through-hole (9) extending from a ground plane (11) of the MSL through the dielectric substrate (2). The construction involves no mismatched portion and can prevent a loss and deterioration in VSWR in the coaxial-line/MSL conversion section, thereby making it possible to obtain satisfactory characteristics.

Abstract: In a microwave multistage amplifier, a shield casing (8) has a partition plate (7) integrally moulded with and disposed in the casing (8); microwave amplifiers (5, 6) are arranged on a dielectric substrate so as to locate the partition plate therebetween; and an upper cover plate (11) is provided which can be screwed to partition plate (7). By virtue of the above-mentioned arrangement, it becomes possible to strictly separate rooms defined in the casing from each other and suppress generation of a surface wave mode of the microwave propagation on the dielectric substrate, thereby assuring an isolation between the amplifiers.

Abstract: A down converter device is disclosed which is used in a satellite communication system to convert a microwave signal to an intermediate frequency signal by the use of a standard signal having a frequency range of several to several tens of MHz, and to apply the intermediate frequency signal to a next stage component. The down converter includes a mixer for producing the intermediate frequency signal indicative of a frequency difference between the standard signal and the microwave signal. A separator is provided which includes a first terminal for receiving the intermediate frequency signal, a second terminal for producing and supplying the intermediate frequency signal to the next stage component and for receiving the standard signal from the next stage component, a first filter for separating the standard signal, and a third terminal for producing the standard signal to the mixing means.