Dual band oscillator circuit using strip line resonators

A dual band oscillator circuit comprising:

• a transistor for oscillation;
• feedback circuits connected across the transistor, each feedback circuit having predetermined impedance values at two or more different frequencies;
• and
• a resonance circuit connected to an input of the transistor, selectable between one of two or more resonance frequencies
• wherein the feedback circuits comprise impedance elements connected between the collector and base, between the base and emitter, and between the emitter and collector of the transistor, respectively, and at least one of the impedance elements comprises a first capacitance element and an inductance element connected in parallel, and a second capacitance element connected in series with the parallel connected elements.

A dual band oscillator circuit comprising:

• a transistor for oscillation;
• feedback circuits connected across the transistor, each feedback circuit having predetermined impedance values at two or more different frequencies;
• and
• a resonance circuit connected to an input of the transistor, selectable between one of two or more resonance frequencies, the resonance circuit including resonators corresponding to the two or more resonance frequencies respectively, and a semiconductor switch element for selecting one of the resonators, the resonance circuit further including a first strip line whose first terminal is grounded, a switch means whose first terminal is connected to a second terminal of the first strip line, and a second strip line connected to a second terminal of the switch means, and either one of a resonance frequency of one of the first and second strip lines and a resonance frequency of both the first and second strip lines is selectable by switching the switch means, a sum of lengths of the first and second strip lines being 1/4 of a wavelength of a first resonance frequency, and a length of the second strip line being 1/2 of a wavelength of a second resonance frequency.

A dual band oscillator circuit comprising:

• a transistor for oscillation;
• feedback circuits connected across the transistor, at least one of the circuits adapted to select one of two or more different impedances;
• and
• a resonance circuit connected to an input of the transistor, having two or more resonance frequencies, the feedback circuits including impedance elements connected between the collector and base, between the base and emitter, and between the emitter and collector of the transistor, respectively, and at least one of the feedback circuits having a selectable impedance;
• wherein at least one of the impedance elements includes a first capacitance element and an inductance element connected in parallel, and a second capacitance element connected in series with the parallel-connected elements.

A dual band oscillator circuit comprising:

• a transistor for oscillation;
• feedback circuits connected across the transistor, at least one of the circuits adapted to select one of two or more different impedances;
• and
• a resonance circuit connected to an input of the transistor, having two or more resonance frequencies, the feedback circuits including impedance elements connected between the collector and base, between the base and emitter, and between the emitter and collector of the transistor, respectively, and at least one of the feedback circuits having a selectable impedance;
• wherein at least one of the impedance elements comprises a first capacitance element, a second capacitance element, and a semiconductor switch element for selecting between the first and second capacitance elements.

A dual band oscillator circuit comprising:

• a transistor for oscillation;
• feedback circuits connected across the transistor, at least one of the circuits adapted to select one of two or more different impedances;
• and
• a resonance circuit connected to an input of the transistor, having two or more resonance frequencies, the feedback circuits including impedance elements connected between the collector and base, between the base and emitter, and between the emitter and collector of the transistor, respectively, and at least one of the feedback circuits having a selectable impedance;
• wherein at least one of the impedance elements comprises a first capacitance element and a semiconductor switch element connected in series, and a second capacitance element connected in parallel with the series-connected elements.