Abstract: A voltage controlled oscillator comprises first oscillating stage for outputting a first frequency signal, second oscillating stage for outputting a second frequency signal different from the first frequency signal, a buffer stage connected with said first and second oscillating stages, the buffer stage receiving said first and second frequency signals to generate an output signal.

Abstract: An antenna switch comprises a first switch device (11) for selectively coupling a common point (e) with a transmit terminal (a) or a receive terminal (c), a second switch device (12) having similar structure to the first switch device (11) for selectively coupling a common point (f) with a first antenna terminal (b) or a second antenna terminal (d), and a filter (13) coupled between the switch devices (11, 12) through capacitors (14, 15). Circuit structure of the first switch device (11) is the same as that of the second switch device (12). Components composing those switch devices are mounted on each layer of a multi-layer substrate with a symmetrical relationship. The number of components is small, and the structure of an antenna switch is simplified. It is used in a portable telephone set for switching transmit/receive operation, and switching antennas.

Abstract: A directional coupler includes first and second dielectric layers, and an intermediate dielectric layer disposed therebetween. The first dielectric layer has one surface formed with a first coupling line, and the second dielectric layer has one surface formed with a second coupling line. Outside the first dielectric layer, there is a third dielectric layer with a grounding electrode on a surface thereof. Outside the second dielectric layer, there is a fourth dielectric layer with a grounding electrode on a surface thereof. The dielectric layers are laminated together so that a dielectric layer is interposed between the grounding electrode and an adjacent one of the coupling lines. The first and second coupling lines are aligned with each other in the direction of laminate. Each of the first and second coupling lines has a spiral configuration including first to fifth sequential portions. The first portion is substantially parallel with an edge of the dielectric layer on which the line is formed.

Abstract: A high frequency signal dividing and/or combining device includes a circuit formed in a laminated sintered dielectric block, input and output terminals grounded through input and output grounding capacitors respectively, inductors (coils) and a resistor. The coil is formed in a coil section having at least one dielectric layer with a conductive coil pattern. The capacitors are formed in at least three dielectric layers including base, intermediate, and upper dielectric layers. The base dielectric layer includes a grounding electrode pattern providing a common grounding electrode for the input and output grounding capacitors. The intermediate dielectric layer overlaps the base dielectric layer so as to cover the grounding electrode pattern.

Abstract: A plurality of inductors and a plurality of capacitors are formed as conductor patterns (3-1 to 3-4, to 4-8, 5) on dielectric layers (1-1 to 1-6) constituting a multi-layer wiring board. A set of circuit elements (inductors and capacitors) required to have the same inductance or capacitance value are formed on the common layers of the multi-layer wiring board. Thus, the circuit elements required to have the same value in the multi-layer wiring board can be manufactured under the same condition (the baking condition for example), so that the variations of the elements can be reduced.

Abstract: A microwave absorber device for a microwave heater having a chamber for cooking with an opening, and a door for closing the opening with a small gap which is a leakage path between the door and the wall of the chamber. The door is provided with a choke cavity at the peripheral portions of the same, the choke cavity having an approximate 1/4 wavelength of length, and an entrance facing the leakage path. The choke cavity is provided with wave absorber which includes ferrite, and/or carbon, at an edge of the entrance or an edge of the cavity. The wave absorber closes also the leakage path. The entrance itself is sealed by dielectric material.