Self-pulsed microwave oscillator

Claim 2

A self-pulsed oscillator comprising: an active element having at least two input terminals and exhibiting a current-voltage characteristic including a negative resistance portion, the d.c. impedance between said terminals of said element decreasing when a direct current bias signal exceeding a predetermined threshold value is applied thereto, a microwave resonant circuit including said element for generating oscillations at a given frequency during periods when the amplitude of said bias signal applied to said terminals exceeds said threshold value, means including a delay device responsive to said decrease in said impedance for causing said signal to periodically exceed said threshold value and operate said element with said resonant circuit to produce said oscillations at said given frequency at intervals determined by the Impedance match between said device and said element.

Claim 3

A self-pulsed oscillator in accordance with claim 1, in which said microwave resonant circuit is a microstrip transmission line circuit having one of said input terminals of said active element coupled to the center of a radial transmission line capacitor, and the other input terminal of said active element coupled to the ground plane of said microstrip transmission line, the complex impedance of said active element being matched to the impedance of a terminating load by a low pass filter connected in series between said radial transmission line capacitor and said terminating load.

Claim 4

A self-pulsed oscillator in accordance with claim 1, including a circuit coupled to said microwave resonant circuit for applying said bias signal across said active element, said circuit being designed to present a high impedance at r.f. frequencies.

Claim 5

A self-pulsed oscillator in accordance with claim 3, said delay device being a two terminal delay line open-circuited at one terminal thereof, means connecting the other terminal of said delay line to said circuit so that, said delay line is responsive to said decrease in said impedance to control the duration of said microwave oscillations.

Claim 6

A self-pulsed oscillator in accordance with claim 3, including means connecting said delay device in series between said circuit and a source of direct current energy.

Claim 7

A self-pulsed oscillator in accordance with claim 3, said responsive means further including a matching resistive device connected with said delay device and said circuit and arranged to control the interval between said microwave oscillations.

Claim 8

In an oscillator of the type including an active element exhibiting a current-voltage characteristic having a negative resistance portion, the direct current impedance across said element decreasing when a bias signal exceeding a predetermined threshold value is applied thereto, whereupon said oscillator oscillates at a given frequency, concurrent with said decreasing impedance, a direct current energy pulse being generated by said element, means for applying said bias signal to said element and said oscillator over a path including means arranged in said path to reflect said pulse back to said element in a manner to lower said bias signal below said threshold value, thereafter to allow said bias signal to again exceed said threshold value, said element and said oscillator being operated by said means to produce said oscillations for predetermined periods, the interval between said periods being determined by the impedance match between said means and said element.

Claim 9

In an oscillator of the type including an active element exhibiting a current-voltage characteristic having a negative resistance portion, the direct current impedance across said element decreasing when a bias signal exceeding a predetermined threshold value is applied thereto, whereupon said oscillator oscillates at a given frequency, concurrent with said decreasing impedance, a direct current energy pulse being generated by said element, means for applying said bias signal to said element and said oscillator over a path including means arranged in said path to reflect said pulse back to said element in a manner to lower said bias signal below said threshold value, thereafter to allow said bias signal to again exceed said threshold value, said element and said oscillator being operated by said means to produce said oscillations for predetermined periods, the interval between said periods being determined by the impedance match between said means and said element.

Claim 10

In an oscillator as claimed in claim 7, said means to reflect said pulse including an open-circuited delay line to one end of which is applied said direct current energy pulse from said element, said reflected pulse being fed back to said element from said one end of said delay line, the time of said periods during which said oscillator oscillates being determined by the parameters of said delay line.

Claim 11

In an oscillator as claimed in claim 8, a matching resistor connected in said path with said delay line and responsive to said pulse received by said delay line and said reflected pulse returned by said delay line, so as to determine the interval between said periods of oscillation.

Claim 12

In an oscillator as claimed in claim 7, said path including an open-circuited delay line, a matching resistor, a high inductance choke, means connecting said choke, said resistor and said delay line in series, the free end of said choke connected to the terminal of a source of direct current energy, means for applying the direct current energy appearing at the junction of said choke and said resistor as said bias signal to said oscillator.