The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 19, 1987
Filed:
Apr. 07, 1986
Theodore F Longshore, Hoffman Estates, IL (US);
Ronald J Wanat, Elgin, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Transmitter combining apparatus includes up to five RF filters (100) coupled to a microstrip combiner (300) for combining up to five input signals for application to a common antenna. The RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) and first and second shield plates (142 and 148) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116), discs (114 and 120) and shield plates (142 and 148) is produced by a compressive force exerted by springs (144-147) of shield plate (142) when the top cover (112) is attached to the aluminum housing (124). The resonant frequency of the RF filter is tuned by means of an aluminum tuning shaft (102) and ceramic tuning core (118) which are positioned by brass bushing (133) in top cover (112). Input signals are coupled to each RF filter via respective input coupling loops (122) and output signals are coupled via corresponding output coupling loops (311) to the microstrip combiner (300). The microstrip combiner (300) includes a circuit board (310) having five transmission lines (601-605) and a short-circuited tuning transmission line (610), all coupled to a junction (620). The microstrip combiner (300) is tuned by means a variable impedance produced by varying the position of a dielectric tuning plate (630) with respect to a the tuning transmission line (610).