Pulsed RF oscillator and radar motion sensor

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and
• circuitry for setting an interval between the first time and the second time, wherein the interval has a length in a range from about 1 nanosecond to about 100 nanoseconds.

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and
• a source of a pulse timing signal;
• and wherein
• the first signal path includes a first switch coupled to the source of the pulse timing signal, which produces the bias-on signal;
• and
• the second signal path includes a delay element, coupled to the source of the pulse timing signal, and a second switch coupled to the delay element which produces the quench signal.

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and wherein the active element comprises a transistor having a first terminal which is one of a base and a gate, the second terminal which is one of a collector and a drain, and a third terminal which is one of an emitter and source.

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and wherein the active element comprises a bipolar transistor.

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and wherein the active element comprises a field effect transistor.

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and including a monopole antenna coupled to the oscillator.

A radio frequency oscillator, comprising:

• a first signal path including a first switch which produces a bias-on signal at a first time;
• and
• a second signal path including a delay element and a second switch coupled to the delay element which produces a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency, wherein the active element comprises a transistor having a first terminal which is one of a base and a gate, a second terminal which is one of a collector and a drain, and a third terminal which is one of an emitter and a source, and
• a resistor connected between the third terminal and the first signal path, which limits amplitude of the oscillation;
• a resistor connected between the second terminal and the second signal path which tends to stabilize the oscillation;
• a first microstrip element coupled to the first terminal, the microstrip tuned for oscillation at approximately the oscillator frequency,
• a second microstrip element coupled to the second terminal arranged adjacent to the first microstrip element for reactive coupling with the first microstrip element, the second microstrip tuned for oscillation at approximately the oscillator frequency.

A motion sensor, comprising:

• a source of a pulse timing signal;
• a first signal path including a first switch coupled to the source of the pulse timing signal, which produces a bias-on signal at a first time;
• a second signal path including a delay element, coupled to the source of the pulse timing signal, and a second switch coupled to the delay element which produces a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency to produce a transmit pulse having a pulse width determined by the first and second times and a pulse repetition pattern determined by the pulse timing signal;
• and
• a detector which produces an output indicating an echo of a transmit pulse mixing with the transmit pulse.

A radio frequency oscillator, comprising:

• a first signal path supplying a bias-on signal at a first time;
• a second signal path supplying a quench signal at a second time after the first time;
• an active element having a first input coupled to the first signal path, a second input coupled to the second signal path, and responsive to the bias-on signal to oscillate at an oscillator frequency, and responsive to the quench signal to cease oscillating at the oscillator frequency;
• and wherein
• the first signal path includes a first switch which produces the bias-on signal;
• and
• the second signal path includes a delay element and a second switch coupled to the delay element which produces the quench signal, and wherein the first switch matches the second switch.