A dielectric resonator microwave bandpass filter includes a printed circuit board supported within a cut-off waveguide, with dielectric resonators and coupling loops on an upper surface of the board and a well beneath the board so that the resonators are well spaced from ground planes. Tuning screws beneath the resonators, and coupling adjustment screws above the board adjacent to the coupling loops and between adjacent resonators, provide for adjustments to provide desired filter characteristics within a wide range. Isolators within the waveguide have ports coupled to the resonators via microstrip transmission lines comprising conductive tracks on the board and ports coupled to coaxial connectors in end walls of the waveguide. The waveguide is formed from a cast body and a flat lid.

Microwave bandpass filters including dielectric resonators mounted on a suspended substrate board

A planar oscillator (9, 109) having a dielectric cavity (25, 125) and which is operative at microwave frequencies, said oscillator consisting of a dielectric material base (10, 110) one surface of which has, superposed thereto, a continuous layer (11,111) of a conductive material which coats portions of said face; the remaining portions (10A, 10B, 110A', 110A", 110B) of the surface have, superposed thereto, strips of a conductive material (12,13,14,112,113,114) which are separate from each other and are electrically connected to an active element (19, 119), a dielectric cavity (25,125) adhering to the opposite surface of the dielectric material base (10,110), the layer of conductive material (11,111) providing a grounding plane and the strips of conductive material (12,13,14,112,113,114) providing transmission and output lines for the oscillator.

Planar microwave oscillator mounted on a dielectric cavity

The paper describes a novel technology for producing micron and submicron gate FET devices, with improved gain and noise performances. The technique is particularly attractive for the production of very low noise devices and is very useful in monolithic circuit fabrication. In the production of high-power devices the technique has the advantage of not requiring complicated interdigitated structures. A noise figure improvement of 0.4 dB at 10 GHz was achieved using this technology. As an example of the developed technique, a two-stage monolithic preamplifier (2.8 dB N.F., 15 dB gain between 11.7 and 12.5 GHz) is described.

Air Bridge Gate FET for GaAs Monolithic Circuits

This invention relates to a planar oscillator (9, 109) having a dielectric cavity (25, 125) and which is operative under microwave frequencies, said oscillator consisting of a dielectric material base (10, 110) one surface of which has, superposed thereto, a continuous layer (11, 111) of a conductive material which coats portions of said face; the remaining portions (10A, 10B, 110A', 110A", 110B) of the surface have, superposed thereto, strips of a conductive material (12, 13, 14, 112, 113, 114) which are separate from each other and are electrically connected to an active element (19,119), a dielectric cavity (25, 125) adhering to the surface away of the dielectric material base (10, 110), the layer of conductive material (11, 111) providing a grounding plane and the strips of conductive material (12, 13, 14, 112, 113, 114) providing transmission and output lines for the oscillator concerned.

Planar oscillator having a dielectric cavity and operative under microwave frequencies

This letter presents that coupling characteristics between a cylindrical TE01delta mode dielectric resonator (DR) and a grounded coplanar waveguide (GCPW) have been examined in terms of S-parameters. The investigation of finite element method simulation (HFSS) agrees well with the measurement results. Unloaded Q values of the DR coupled with three uniform CPWs are compared with those of the DR coupled with microstrip line. The comparison shows that the DR coupled with the GCPW has the highest unloaded Q

$S$ -Parameter Extraction on Coupling Between DR and GCPW

The coupling of a dielectric resonator through coplanar waveguides is experimentally studied and the feasibility of very selective microwave circuits, where the resonator is placed below the active and passive circuit components, is demonstrated. The design and the operation of high-stability feedback-type coplanar oscillators are reported. The possibility of mounting a monolithic chip over a high-Q dielectric cavity, avoiding unwanted resonator coupling anywhere in the circuit, is demonstrated. This allows the sealing of the overall circuit in a practical low-size case. Finally, the performances of a test monolithic chip carrying two different oscillators are stressed.

P. Bergamini

Papers

GaAs Monolithic Circuits Mounted Over High Q Dielectric Resonators