Abstract: A high-frequency circuit device includes a substrate and a high-frequency circuit. The high-frequency circuit is provided on the substrate and has a signal line. The signal line is configured with a slot line provided by electrodes that are arranged side-by-side with a space therebetween on the substrate. The slot line can facilitates circuit design compared to a microstrip line and has significantly low conduction loss compared to a coplanar line, and can improve the Q-value of the high frequency circuit. This can provide an improved high-frequency circuit device having small phase noise. The high-frequency circuit device, which also serves as an oscillator, employs a slot output and thus can provide an advantage of better continuity for a class-B push-pull amplifier that operates more efficiently than a class-A one.

Abstract: A dielectric resonator device includes a dielectric substrate. Electrode films are formed on the front and back surfaces of the dielectric substrate, respectively. A TE010-mode resonator is constituted by two circular openings which oppose each other and which are formed in the electrode films. Two opposing slots formed in the electrode films constitute a planar dielectric transmission line (PDTL). The PDTL is connected to the TE010-mode resonator. An excitation section is formed by extending two portions of each electrode film on two side of each slot into each opening.

Abstract: A voltage controlled oscillator includes a resonant circuit which is connected with an active circuit. In the resonant circuit, a variable capacitance diode is connected with a resonator via a transmission line, and a capacitive circuit is connected in parallel with the variable capacitance diode. By setting the length of the transmission line to an appropriate value ranging from, for example, about one quarter to about one half of the wavelength of the resonant frequency, the frequency change width can increase, while maintaining the frequency linearity because of connection of the capacitive circuit.

Abstract: A field-effect transistor device includes an active area on a semiconductor substrate and a gate electrode, a source electrode, and a drain electrode are disposed on the surface of the active area, so as to define an FET portion. An electrode defining a line for connection to the gate, an electrode defining a line for connection to the source, and an electrode defining a line for connection to the drain are disposed on the semiconductor substrate. The electrodes define a slot line on the input side for supplying a signal to the FET portion, and a slot line on the output side from which a signal of the FET portion is output. The gate electrode has a shape which extends along the direction that approximately perpendicular to the conduction direction of the signal through the slot line on the input side.

Abstract: A high-frequency oscillation circuit includes a resonance circuit and an active circuit. The active circuit includes a field-effect transistor and a capacitor. An impedance-conversion circuit including a high-impedance line, a capacitive stub, and a connecting line such as wire, is connected between the active circuit and the resonance circuit. Accordingly, the impedance-conversion circuit can convert the characteristic impedance of the resonance circuit so that the absolute value of the reflection coefficient of the active circuit increases. As a result, the oscillation conditions can be easily fulfilled.