Trw Limited

John C Tippet

Ming-Jong Shiau

Michael Vieru

A multioctave multiplexer (10) with multiple independent filter channels with a circuit topology that employs a planar circuit segment (18) and conventional combline resonator circuits (38), (40) and (42). The planar circuit segment (18) forms a common input (28) etched on a substrate and concurrently feeds RF signals to the independent channels (12), (14) and (16). The first planar circuit segment (18) comprises two unit elements (51) and (52) and a .pi.-section capacitor network (54), (56) and (58). The second combline circuit segment (38) comprises shunt resonators (38a), (38b), and (38c) and inter-resonator inductors (44a), (44b) and (44c) . The first and second circuit segments generate a number of transmission zeros on a complex plane that is 2 at DC, 2N-4 at one-quarter wavelength and 2 at the complex frequency of S=+/-1 in the complex plane. The planar common junction multiplexer provides the advantages of low manufacturing cost and the ease of assembly of the prior art without sacrificing any loss in performance and equivalent performance of the more costly high precision conventional combline resonator multiplexers.

Combline multiplexer with planar common junction input

A small, high performance MMIC compatible filter having a suspended dielectric substrate transmission medium to achieve superior Q. The substrate is suspended within an opening formed in a surrounding housing and has a plurality of conductive paths disposed thereon. An elliptical function response provides optimum filter size and insertion loss for a given required out-of-band rejection by making use of finite transmission zeroes on each side of the passband.

Miniature, high performance MMIC compatible filter

A common input junction, multioctave, printed microwave multiplexer. In a first preferred embodiment the multiplexer is in the form of a microstrip. In an alternative preferred embodiment the multiplexer is provided in the form of a suspended substrate multiplexer. Each of the preferred embodiments include independently formed first, second and third channels each having an input and an output, with the input of each channel being coupled together and to a common input junction. The channels are adapted to simultaneously receive radio frequency (RF) signals in the range of, for example, about 3 to 18 GHz. The first independent channel provides an RF output signal having a frequency range of preferably about 3 to 5.5. GHz. The second independent channel provides an RF output signal having a frequency range of about 5.5 to 10 GHz, and the third independent channel provides an RF output signal having a frequency range of about 10 to 18 GHz. The multiplexer is significantly smaller in size and weight than conventional combline and suspended substrate multiplexers, provides significantly fewer component parts, and requires no calibration adjustments.

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Rancho Palos Verdes, CA, United States of America

John C Tippet