Qualcomm Incorporated

Omnitracs, LLC

William A Johnston

Mohammad Ali Tassoudji

Scott Aldern

Jeff Devereux

Fritz Gerd Berger

A coaxial to microstrip transition is introduced in a multi layer mixed dielectric printed circuit board environment that provides a 50 Ohm impedance system between a coaxial antenna feed and a surface mount diplexer at Ku-band frequencies. The 50 Ohm transition from the coaxial antenna feed to the diplexer at microwave frequencies lossy FR-4 style laminate is provided by constructing a PCB internal coax using the center conductor of the antenna feed and a dual ring of plated through hole VIAs. The transition from the PCB internal coax to the microstrip section of the high frequency laminate PCB layer uses a 'D'-style opening in the ground layer and a VIA ring arrangement between the layers to optimize or tune the performance of the transition. Additional features in the interface construction are implemented to guaranty that its microwave and mechanical performance does not degrade in extreme environmental conditions.

Ku-band coaxial to microstrip mixed dielectric PCB interface with surface mount diplexer

A compact Ku band microwave diplexer configured as a three port surface mount component on a miniature alumina substrate. Input signals occurring at a common port having frequencies within a first pass band are passed to a second port while being isolated from signals occurring at a third port. Signals occurring at the third port are passed to the common port while being isolated from the signals at the second port. A microstrip dual spur line filter is used combined with open circuit stubs to provide enhanced second harmonic suppression on the transmit side, while using a coupled line microstrip filter on the receive side. This approach allows for compact size and automated component assembly through pick and place and reflow manufacturing techniques.

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Poway, CA, United States of America

William A Johnston