Microstrip microwave oscillators

Claim 2

A microstrip microwave oscillator circuit tuned simultaneously at fundamental and second harmonic frequencies comprising a strip resonator separated from a ground plane by an insulator, a solid-state microwave oscillator device connected between said strip resonator and ground plane, and means for applying a bias voltage to said oscillator device, an orthogonally extending output microstrip circuit separated from a ground plane by an insulator and including a coupling microstrip line that is series capacitance coupled to said strip resonator in alignment with said oscillator device and terminated by a microstrip low pass filter network which passes fundamental frequency energy while reflecting second harmonic energy, said oscillator circuit being tuned simultaneously to parallel resonance at the fundamental and second harmonic frequencies to apply to said oscillator device a radio frequency voltage that is the sum of the fundamental and second harmonic voltages and produces an output fundamental frequency voltage with enhanced efficiency.

Claim 3

A circuit according to claim 1 wherein said strip resonator is tuned to parallel resonance with the circuit capacitance at the fundamental frequency, and said low pass filter network provides a minimum impedance plane at the second harmonic frequency near the end of said coupling line, and the inductance of said coupling line is tuned with the circuit capacitance to obtain second harmonic tuning.

Claim 4

A circuit according to claim 1 wherein said low pass filter network provides an effective open circuit at the second harmonic frequency near the end of said coupling line, and said coupling line is approximately a quarter wavelength line at the second harmonic frequency, and said oscillator device is mounted intermediate the ends of said strip resonator at distances to obtain tuning with the circuit capacitance at both the fundamental and second harmonic frequencies.

Claim 5

A circuit according to claim 1 wherein said low pass filter network is an open-ended-line network, and said series coupling capacitance is dimensioned to obtain fundamental frequency impedance matching between said oscillator device and a load.

Claim 6

A microstrip microwave oscillator circuit tuned simultaneously at fundamental and second harmonic frequencies comprising a plurality of orthogonally arranged conductive microstrip components separated from a conductive ground plane by an insulating layer including a strip resonator, a solid-state microwave oscillator device connected between said strip resonator and ground plane, and means for applying a bias voltage to said oscillator device, a capacitively coupled output microstrip circuit extending orthogonal to said strip resonator in alignment with said oscillator device and comprising a coupling line terminated by an open-ended-line filter network which is in turn connected to an output line supplying fundamental frequency output voltage, wherein said open-ended-line network passes fundamental frequency energy while reflecting second harmonic frequency energy, and provides an effective short circuit at the second harmonic frequency near the end of said coupling line, the inductance of said coupling line is tuned with the circuit capacitance to obtain second harmonic frequency tuning, and the inductance of said strip resonator is tuned with the circuit capacitance to obtain fundamental frequency tuning.

Claim 7

A microstrip microwave oscillator circuit tuned simultaneously at fundamental and second harmonic frequencies comprising a plurality of orthogonally arranged conductive microstrip components separated from a conductive ground plane by an insulating layer including a strip resonator, a solid-state microwave oscillator device connected between said strip resonator and ground plane, and means for applying a bias voltage to said oscillator device, a capacitively coupled output microstrip circuit extending orthogonal to said strip resonator in alignment with said oscillator device and comprising a coupling line terminated by an open-ended-line filter network which is in turn connected to an output line supplying fundamental frequency output voltage, wherein said open-ended-line network passes fundamental frequency energy while reflecting second harmonic frequency energy, and provides an effective short circuit at the second harmonic frequency near the end of said coupling line, the inductance of said coupling line is tuned with the circuit capacitance to obtain second harmonic frequency tuning, and the inductance of said strip resonator is tuned with the circuit capacitance to obtain fundamental frequency tuning.

Claim 8

A circuit according to claim 5 wherein said capacitively coupled output circuit includes a series coupling capacitance formed between said strip resonator and coupling line to provide fundamental frequency impedance matcHing between said oscillator device and a load, and further including a pair of strip transformers between said open-ended-line filter network and output line for additional impedance matching at the fundamental frequency.

Claim 9

a circuit according to claim 5 wherein said strip resonator has a radio frequency bypass capacitor connected to each end thereof, and said solid state oscillator device is mounted at the midpoint of said strip resonator, and said open-ended-line filter network is made of longitudinal and orthogonal components with the same characteristic admittance as said coupling line and output line and a sum of lengths equal to one quarter wavelength measured at the fundamental frequency.

Claim 10

A circuit according to claim 5 wherein all of said microstrip components are printed circuit components formed on one surface of said insulating layer, and said ground plane is adjacent the other surface of said insulating layer.

Claim 11

A microstrip microwave oscillator circuit tuned simultaneously at fundamental and second harmonic frequencies comprising a plurality of orthogonally arranged conductive microstrip components separated from a ground plane by an insulating layer including a strip resonator, a solid state microwave oscillator device connected between said strip resonator and ground plane, and means for applying a bias voltage to said oscillator device, a capacitively coupled output microstrip circuit extending orthogonal to said strip resonator in alignment with said oscillator device and comprising a coupling line terminated by an open-ended-line filter network which is in turn connected to an output line supplying fundamental frequency output voltage, wherein said open-ended-line filter network passes fundamental frequency energy while reflecting second harmonic energy, and provides an open circuit at the second harmonic frequency near the end of said coupling line, and said solid state oscillator device is mounted intermediate the ends of said strip resonator at distances to obtain tuning with the circuit capacitance at both the fundamental and second harmonic frequencies.

Claim 12

A microstrip microwave oscillator circuit tuned simultaneously at fundamental and second harmonic frequencies comprising a plurality of orthogonally arranged conductive microstrip components separated from a ground plane by an insulating layer including a strip resonator, a solid state microwave oscillator device connected between said strip resonator and ground plane, and means for applying a bias voltage to said oscillator device, a capacitively coupled output microstrip circuit extending orthogonal to said strip resonator in alignment with said oscillator device and comprising a coupling line terminated by an open-ended-line filter network which is in turn connected to an output line supplying fundamental frequency output voltage, wherein said open-ended-line filter network passes fundamental frequency energy while reflecting second harmonic energy, and provides an open circuit at the second harmonic frequency near the end of said coupling line, and said solid state oscillator device is mounted intermediate the ends of said strip resonator at distances to obtain tuning with the circuit capacitance at both the fundamental and second harmonic frequencies.

Claim 13

A circuit according to claim 9 wherein said capacitively coupled output circuit includes a series coupling capacitance formed between said strip resonator and coupling line to provide fundamental frequency impedance matching between said oscillator device and a load, and said coupling line has a length equal to a quarter wavelength at the second harmonic frequency.

Claim 14

A circuit according to claim 10 wherein said strip resonator is a shorted-line resonator with radio frequency bypass capacitors at each end.

Claim 15

A circuit according to claim 10 wherein said strip resonator is a shorted-line, open-ended resonator with a radio frequency bypass capacitor at one end thereof.

Claim 16

A circuit according to claim 10 wherein all of said microstrip components are printed circuit components formed on one surface of said insulating layer, and said ground plane is adjacent the other surface of said insulating layer.

Claim 17

A circuit according to claim 10 wherein said strip resonator has a radio frequency bypass capacitor at one end thereof with one plate formed by extending said strip resonator, said means for applying a bias voltage being a unidirectional voltage source connected to said bypass capacitor plate, and wherein said solid state oscillator device is a transferred-electron diode.