Filtronic Plc

John David Rhodes

Ian Charles Hunter

An amplifier comprising a field effect transistor, a terminating network comprising inductors connected in series separated by capacitors connected in parallel, a filter and a load, wherein the values of the capacitors and inductors are arranged to present open circuits to a predetermined number of odd harmonics of a signal frequency being amplified, and to present short circuits to a predetermined number of even harmonics of the signal frequency, wherein the normalised values of the inductors and capacitors of the terminating network are selected using the following procedure: Let g=Cr odd=Lr even then g=1, gg=(a); gg=(b), r=2&#x2192;2m&#x2212;1 and gg=(c) where (m&#x2212;1) represents the predetermined number of odd harmonics which are presented with an open circuit 

Amplifier

A method of producing filters using lower unloaded Q factor components than filters with the same performance characteristics but requiring higher unloaded Q factor components is disclosed. The method includes the steps of defining a desired filter characteristic and applying an algorithm which provides a filter having infinite Q factor elements and having a theoretical characteristic corresponding to the desired characteristic transformed to a compensate for the difference between finite Q factor and infinite Q factor elements.

Reflection-mode filter and method with a constant loss off-set

A microwave frequency composite resonator comprising a metal housing having an internal surface and defining a resonator cavity, a dielectric member having a top face and a bottom face and a conducting plate. The dielectric member is located within the resonator cavity and the bottom face of the dielectric member directly abuts the internal surface of the metal housing and the conducting plate directly abuts the top face of the dielectric member.

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Ilkley, United Kingdom

John David Rhodes