Abstract:
An oscillator body 10 defines a waveguide 11 in which is supported a Gunn diode 15. The Gunn diode 15 is thermally and electrically connected to a surface of a heat sink having a cylindrical main body 40 which is supported in the body 10 by an interference or tight sliding fit. A frequency tuning probe 65 is supported by an interference fit for longitudinal displacement into the region between a lower face 66 of an RF choke 13, in order to allow the frequency of operation of the oscillator to be controllably adjusted. A cylindrical short circuit 62 is supported in a cylindrical portion 61 of the waveguide 11 by an interference fit, whereby the output power of the oscillator can be accurately and reliably adjusted. A rectangular cross-section portion of the waveguide 11 meets the cylindrical portion 61 with a step transition.
Abstract:
The four-diode bridge (14) is positioned within the cavity (10) of a Gunn diode (12) 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 (26) in order to provide a microwave oscillator with multiple-channel operation. The diode bridge provides a feedback signal indicative of the phase of the cavity oscillation. The feedback signal is applied to a varactor (24) which pretunes the Gunn diode oscillator and thereby provides phase-locked control.
Abstract:
Oscillateur comporte un élément à résistance négative (18) et un résonateur diélectrique (19) disposé à la surface d'un substrat (13, 14) situé à l'intérieur d'un boîtier (10), dans lequel le boîtier (10) est muni d'un dégagement situé au dessus du résonateur diélectrique (19). Application au domaine des hyperfréquences.
Abstract:
A tuning device for an RF cavity or RF antenna has an actuator (7) mechanically coupled (8) to a tuning element (14), such as a tuning pin of an RF cavity. The actuator is an SMA-wire actuator capable of linear movement connected via a mechanical link to an RF tuning pin such that the tuning pin is moveable by the actuator in and out of the RF-cavity. The actuator may comprise a straight SMA wire or a bowstring SMA wire coupled to a return spring, or it may be an SMA-wire actuator comprising a pair of opposed bowstring-actuators (1,2) eliminating the requirement for a return spring and with a design methodology that allows a wide range of performance specifications and envelope sizes.
Abstract:
The present invention relates to an oscillator device (1) comprising a first amplifier unit (2) and a waveguide cavity resonator (3) with a cavity (11) and a first tuning device (4) mounted in the cavity (11). The cavity (11) has a first cavity length (a) running between two opposing inner walls (5,6) where a resonance frequency (f r ) of the resonator (3) is dependent on the first cavity length (a). The first tuning device (4) comprises at least one row (13, 14, 15) of switches (16) that are electrically openable and closable. Each row (13, 14, 15) is arranged to constitute an electrically conducting connection between said opposing inner walls (7, 8) when the switches of said row are closed. The first amplifier unit (2) is electrically connected to the waveguide cavity resonator (3) by means of a first (35) and a second connector (36) which are mutually out of phase with each other. The first amplifier unit (2) further comprises a first amplifier arrangement (37) and a tuneable bias connection (38).
Abstract:
An oscillator body 10 defines a waveguide 11 in which is supported a Gunn diode 15. The Gunn diode 15 is thermally and electrically connected to a surface of a heat sink having a cylindrical main body 40 which is supported in the body 10 by an interference or tight sliding fit. A frequency tuning probe 65 is supported by an interference fit for longitudinal displacement into the region between a lower face 66 of an RF choke 13, in order to allow the frequency of operation of the oscillator to be controllably adjusted. A cylindrical short circuit 62 is supported in a cylindrical portion 61 of the waveguide 11 by an interference fit, whereby the output power of the oscillator can be accurately and reliably adjusted. A rectangular cross-section portion of the waveguide 11 meets the cylindrical portion 61 with a step transition.
Abstract:
A microwave cavity oscillator has a semiconductor device, for example a transistor (50) for exciting the cavity (12) to oscillate. The device is mounted upon a substrate which is itself mounted, conveniently soldered, upon a carrier (32) which is releasably secured in a chamber (14) adjacent the cavity. The carrier (32) and substrate (42) are mounted so that the device (50) is coupled to the cavity via a hole (22) 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 (24) surrounding a hole communicating with the cavity. The other end of the carrier is urged by spring means (44) to positively and accurately locate the carrier relative to the cavity. A part (46) of the substrate extends through the hole and into the cavity. The transistor (50) is mounted on the part within the hole and the part within the cavity serves as a capacitive coupling probe (48).
Abstract:
A microwave cavity oscillator has a semiconductor device, for example a transistor (50) for exciting the cavity (12) to oscillate. The device is mounted upon a substrate which is itself mounted, conveniently soldered, upon a carrier (32) which is releasably secured in a chamber (14) adjacent the cavity. The carrier (32) and substrate (42) are mounted so that the device (50) is coupled to the cavity via a hole (22) 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 (24) surrounding a hole communicating with the cavity. The other end of the carrier is urged by spring means (44) to positively and accurately locate the carrier relative to the cavity. A part (46) of the substrate extends through the hole and into the cavity. The transistor (50) is mounted on the part within the hole and the part within the cavity serves as a capacitive coupling probe (48).
Abstract:
A millimeter wave microstrip oscillator utilizing either a pulsed or CW IMPATT diode as the active element provides relatively high power output not available with a GUNN diode. The circuit comprises a block of a conductive metal having a channel of rectangular cross-section formed therein and including a cylindrical well formed inwardly in the block from the floor of the channel. A packaged IMPATT diode of either the pulsed or CW variety fits into the well with the cap portion of the package coplanar with the microstrip circuit pattern when the microstrip rests on the floor of the channel. The pattern includes a shunt open circuit stub and an impedance transformer connected to the terminals of the IMPATT diode for effectively matching the diode's complex impedance with the load. A conductive cover is secured to the block and a laterally and vertically movable tuning screw passes through the cover for fine tuning the oscillator's output frequency and power. The circuit is capable of producing CW or pulsed signals with appropriate choice of IMPATT diode bias signal (pulsed or DC), microstrip circuit pattern dimensions and tuning screw diameter and position.