Waveguide frequency multiplier wherein waveguide cutoff frequency is greater than input frequency

Claim 2

A waveguide frequency multiplier for microwave frequencies comprising a section of waveguide having a bottom cutoff frequency that is above an input frequency that is to be multiplied, a movable probe extending through a narrow wall of the waveguide and adapted to be adjusted to a length of one-quarter wavelength of input frequency to thus define a resonant coaxial cavity across the waveguide, input means energizing said probe at a frequency to be multiplied, a varactor diode having an enlarged metal end extending into the waveguide from a broad wall thereof and disposed adjacent said probe for capacitive coupling thereto and launching doubled signals, said varactor diode having the end thereof opposite said metal end electrically grounded to said waveguide, and movable electrical shorting means extending across said waveguide on the opposite side of said probe from said varactor and adjustable to reflect frequency multiplied signals from said enlarged diode end back in phase with said signals propagated in the opposite direction out of the waveguide.

Claim 3

The multiplier of claim 1 further defined by said input means comprising a coaxial cable having the outer conductor connected to said waveguide and the inner conductor extending through an opening in a waveguide narrow wall into connection with said probe within said waveguide.

Claim 4

The multiplier of claim 1 further defined by the internal perimeter of said waveguide about said probe having a total length less than one-half wavelength of input frequency whereby only the transverse electric and magnetic field mode is excited.

Claim 5

The multiplier of claim 1 further defined by said varactor diode being mounted in the middle of the broad wall of said waveguide.

Claim 6

The multiplier of claim 1 further defined by an rf choke wire extending from the enlarged metal end of said varactor diode orthogonally to the direction of diode extension into the waveguide, a bias resistor grounding said choke wire, and means capacitively shunting said resistor to DC ground.

Claim 7

A waveguide frequency multiplier for microwave frequencies comprising a waveguide section having an open output end and a movable end wall at the opposite end, said waveguide having parallel narrow walls connected by parallel broad walls, the waveguide having a lower cutoff frequency above the frequency of an input frequency to the waveguide, means coupling an input signal into the waveguide and including a probe extending through a narrow wall of the guide and being adjustable to extend one-quarter wavelength of input signal into the waveguide in proximity to said movable end wall to establish a coaxial resonant cavity in the waveguide at said input frequency, a varactor diode mounted upon a broad wall of the waveguide therein and extending perpendicularly to said probe adjacent thereto and toward the open waveguide end therefrom with means capacitively coupling the diode to the probe for excitation of the diode, and a bias limiting resistor connected in shunt with said diode and means for AC decoupling the diode and resistor, said movable end wall being positioned to establish resonance at a desired output frequency of the diode whereby energy of such frequency is propagated along the waveguide to the open end thereof.

Claim 8

A waveguide frequency multiplier for microwave frequencies comprising a waveguide section having an open output end and a movable end wall at the opposite end, said waveguide having parallel narrow walls connected by parallel broad walls, the waveguide having a lower cutoff frequency above the frequency of an input frequency to the waveguide, means coupling an input signal into the waveguide and including a probe extending through a narrow wall of the guide and being adjustable to extend one-quarter wavelength of input signal into the waveguide in proximity to said movable end wall to establish a coaxial resonant cavity in the waveguide at said input frequency, a varactor diode mounted upon a broad wall of the waveguide therein and extending perpendicularly to said probe adjacent thereto and toward the open waveguide end therefrom with means capacitively coupling the diode to the probe for excitation of the diode, and a bias limiting resistor connected in shunt with said diode and means for AC decoupling the diode and resistor, said movable end wall being positioned to establish resonance at a desired output frequency of the diode whereby energy of such frequency is propagated along the waveguide to the open end thereof.

Claim 9

The multiplier of claim 6 further defined by said input means comprising a metal bushing about said probe and engaging said waveguide and engaging said probe adjacent the inner end thereof, and a coaxial connector secured to the waveguide narrow wall at an opening therein adjacent the probe and having a central coaxial conductor extending through said opening into contact with sAid bushing at a distance from the waveguide wall that established an rf impedance matching the impedance of a coaxial input cable to be attached to the coaxial connector.

Claim 10

The multiplier of claim 6 further defined by a mounting block and heat sink secured to the exterior of said waveguide at a broad wall thereof, metallic diode mounting means threaded in said mounting block and extending through the waveguide broad wall with said diode mounted on the inner end thereof for adjustably positioning the diode in the waveguide and electrically grounding one side of the diode, and a metal hat mounted in the waveguide upon an insulator in line with the diode and adjacent said probe for engagement with said diode to capacitively couple the diode and probe and to launch frequency multiplied signals from the diode into the waveguide.

Claim 11

A waveguide frequency doubler for microwave frequencies comprising, a single waveguide section having a first open output end and a second end with an adjustably movable end wall thereacross, input means including a coaxial input line having the outer conductor connected to a narrow wall of the waveguide adjacent the second waveguide end and the central conductor extending through the narrow wall into the waveguide, and a metal probe adjustably extending into said waveguide through said narrow wall and having said central coaxial conductor connected thereto adjacent the inner probe end, said probe length being adjustable to one-quarter wavelength of input frequency, a shunt varactor within said waveguide and having a first end connected to a broad wall of said waveguide, a metal element disposed within said waveguide adjacent said probe on the opposite side thereof from said movable end wall and engaging a second end of said varactor to capacitively couple input energy to said varactor and to launch varactor signals into the waveguide, and said waveguide having a lower cutoff frequency above the input frequency to prevent coupling of the input signals to the output and said varactor output being orthogonal to the input to decouple same from the input, whereby adjustment of the waveguide end wall reinforces frequency doubled signals from the varactor radiated from said metal element toward the open waveguide end.

Claim 12

A waveguide frequency doubler for microwave frequencies comprising, a single waveguide section having a first open output end and a second end with an adjustably movable end wall thereacross, input means including a coaxial input line having the outer conductor connected to a narrow wall of the waveguide adjacent the second waveguide end and the central conductor extending through the narrow wall into the waveguide, and a metal probe adjustably extending into said waveguide through said narrow wall and having said central coaxial conductor connected thereto adjacent the inner probe end, said probe length being adjustable to one-quarter wavelength of input frequency, a shunt varactor within said waveguide and having a first end connected to a broad wall of said waveguide, a metal element disposed within said waveguide adjacent said probe on the opposite side thereof from said movable end wall and engaging a second end of said varactor to capacitively couple input energy to said varactor and to launch varactor signals into the waveguide, and said waveguide having a lower cutoff frequency above the input frequency to prevent coupling of the input signals to the output and said varactor output being orthogonal to the input to decouple same from the input, whereby adjustment of the waveguide end wall reinforces frequency doubled signals from the varactor radiated from said metal element toward the open waveguide end.

Claim 13

A waveguide frequency multiplier for microwave frequencies comprising a waveguide section having an open output end, an end wall at the opposite end, and a first pair of parallel walls that are perpendicular to a second pair of parallel walls, the waveguide having a lower cutoff frequency that is greater than the frequency of an input signal, means coupling the input signal into the waveguide and including a probe extending through one of the first walls into the waveguide and operable to establish a coaxial resonant cavity across the waveguide at the input frequency, a varactor diode mounted in the waveguide on one of the second walls to extend perpendicular to said probe and second walls, and an enlarged electrically conductive member spaced from said walls in the waveguide and engaging one end of said diode for capacitively coupling the diode to the probe for excitation of the diode and launching frequency double signals from the latter into the waveguide, said diode being spaced in the order of one-quarter wavelength from the end wall whereby frequency doubled signals reflected from the latter reinforce frequency doubled signals from the diode radiated toward the open end of the waveguide.

Claim 14

A waveguide frequency multiplier for microwave frequencies comprising a waveguide section having an open output end, an end wall at the opposite end, and a first pair of parallel walls that are perpendicular to a second pair of parallel walls, the waveguide having a lower cutoff frequency that is greater than the frequency of an input signal, means coupling the input signal into the waveguide and including a probe extending through one of the first walls into the waveguide and operable to establish a coaxial resonant cavity across the waveguide at the input frequency, a varactor diode mounted in the waveguide on one of the second walls to extend perpendicular to said probe and second walls, and an enlarged electrically conductive member spaced from said walls in the waveguide and engaging one end of said diode for capacitively coupling the diode to the probe for excitation of the diode and launching frequency double signals from the latter into the waveguide, said diode being spaced in the order of one-quarter wavelength from the end wall whereby frequency doubled signals reflected from the latter reinforce frequency doubled signals from the diode radiated toward the open end of the waveguide.

Claim 15

The multiplier according to claim 10 including means for tuning the waveguide cavity formed between said diode and the end wall.