Abstract:
A microwave cavity oscillator has a semiconductor device, for example a transistor for exciting the cavity to oscillate. The device is mounted upon a substrate which is itself mounted, conveniently soldered, upon a carrier which is releasably secured in a chamber adjacent the cavity. The carrier and substrate are mounted so that the device is coupled to the cavity via a hole extending therebetween and can be removed and installed as a sub-assembly to facilitate tuning and other adjustments in a test bed. In preferred embodiments one end of the carrier is located in spigot-and-socket fashion in a recess surrounding a hole communicating with the cavity. The other end of the carrier is urged by spring means to positively and accurately locate the carrier relative to the cavity. A part of the substrate extends through the hole and into the cavity. The transistor is mounted on the part within the hole and the part within the cavity serves as a capacitive coupling probe.
Abstract:
A broad-band cavity-tuned transistor oscillator includes a field effect device having capacitive feedback from source to drain and having a gate capacitively coupled to a cavity for producing an output signal that is frequency selectable according to cavity resonance, which resonance is determined by translation position of a mechanical tuning plunger coupled to the cavity and the degree of capacitive feedback.
Abstract:
Disclosed is microwave oscillator or amplifier circuitry which is tunable over a wide bandwidth and which includes an improved variable loading on a negative resistance semiconductor diode, such as an IMPATT diode. This loading is provided in mutually perpendicular directions closely adjacent the diode. In one direction, a DC bias connection is mounted together with an adjustable coaxial filter thereon, and this filter serves as a series tuning element for the diode. A movable short is mounted for adjustment in a direction perpendicular to that of the above coaxial filter and provides parallel tuning for the diode. These series and parallel tuning elements are operative to match the real and imaginary components of the diode impedance to the real and imaginary components of the load impedance, respectively, at a particular operating frequency, thereby maximizing the power transfer and the DC to RF conversion efficiency of the circuitry. For ease of frequency adjustment, all of the frequency dependent parameters of the circuitry are contained in a removable and replaceable insert which fits securely into the waveguide housing.
Abstract:
This relates to a broadband injection-tuned Gunn diode microwave oscillator module. The module includes a Gunn diode and a microwave resonant cavity. The resonant cavity is a multi-tuned circuit to present the Gunn diode with its negative impedance over the requisite frequency band. The cavity is an evanescent mode waveguide. Tuning is accomplished solely by an injection locking signal which modifies the impedance of the cavity to match the Gunn diode over the requisite frequency band. This type of tuning eliminates the need for either electronic tuning of the Gunn diode and/or mechanical tuning of the cavity.
Abstract:
A microwave oscillator which is intended for a semiconductor element and which is accommodated in a ridge-type waveguide. The waveguide is formed on the one side by a portion of small height which is closed by a short-circuit element, and on the other side by a portion having a progressively increasing height which is provided with a resonant structure. The resonant structure is formed by a thin vertical pin and by two further pins which are arranged perpendicular to the side walls of the wave guide and which can be axially adjusted. The assembly formed by these three components constitutes a transmission line which enables transmission of a microwave according to the T.E.M.-mode.
Abstract:
A four-diode bridge is positioned within the cavity of a Gunn diode oscillator. A subharmonic signal is applied to the diode bridge and the diode bridge couples an odd harmonic of the injected signal into the cavity. The cavity is thus caused to resonate at the odd harmonic of the injected signal. The injected signal can be changed using a frequency synthesizer in order to provide a microwave oscillator with multiple-channel operation. The diode bridge provides a feedback signal indicative of the phase of cavity oscillation. The feedback signal is applied to a varactor which pretunes the Gunn diode oscillator and thereby provides phase-locked control.
Abstract:
A microwave frequency oscillator utilizing a push-push configuration to provide a low noise highly stable output signal at twice the frequency of a single resonator. The single resonator is connected in the feedback loop of two amplifiers. Additional circuit elements insure the proper oscillation conditions and relative phase are maintained. The use of a single resonator makes possible the application of various noise reduction techniques.