Motorola Corporation

Brian E Bedard

Bertho Kjell Boman

Gary Robert Geller

A thin film structure is provided with the capability of low-power laser tuning and trimming. Trim windows in a plated ground plane are incorporated to allow automated tuning procedures using relatively low-power lasers. The trim windows are conductive, but the heavier layer of plated copper is omitted from those areas, leaving only the titanium/evaporated copper/ gold layers. The method can also provide for areas of bare substrate if desired.

Method of tuning apparatus by low power laser beam removal

Stripline filters and the like have one or more elongated resonator conductors positioned on a dielectric substrate which is backed by a ground plane conductor, with the response frequency being dependent primarily on the length of the resonator. A wide apron conductor is connected to the grounded end of the resonator and to the ground planes. The resonator and apron can be formed by use of a mask such that errors in alignment of the mask do not change the length of the resonator or the point of connection to the grounding apron. The apron, because of its width, has low transmission line impedance to the ground plane which is not changed by changes in configuration or position of the mask, so that it effectively grounds the resonator at the end thereof connected to the apron. A second dielectric substrate backed by a ground plane conductor may be placed on the resonator conductor. The filter may have a plurality of resonators connected to grounding aprons, and a plurality of resonators can be connected to the same apron. In this case it may be desired to place a notch or cut-out in the apron between the connection of the resonators thereto, to interrupt spurious couplings between such resonators through the apron.

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Lochmere, NH, United States of America

Brian E Bedard