Fujitsu Corporation

Berex Corporation

Fujitsu Compound Semiconductor, Inc.

Edmar Camargo

Yoji Ohashi

Wayne Kennan

Debasis Dawn

Hyung Mo Yoo

Seokho Bang

A cascode amplifier circuit having substantial linearity, while maintaining other advantages of cascode amplifiers such as relatively high input-to-output isolation and relatively high gain. The cascode amplifier circuit also provides substantially matched impedance between input and output, at least within a selected frequency band, with the effect of providing a circuit that is well-suited for use in a communication system. The cascode amplifier circuit includes feedback loops, such as for example DC feedback loops and AC feedback loops, and bias optimization, with the effect of improving linearity, maintaining gain, minimizing return loss, and providing a relatively high dynamic range.

Linearity enhancement on cascode gain block amplifier

Disclosed are planar structures for coupling electromagnetic signals between planar transmission lines and waveguides. A preferred exemplary structure comprises a shielded patch antenna and one or more capacitive diaphragms disposed adjacent to the patch antenna. This structure is advantageous to MMIC modules in connecting from a planar transmission line of a substrate carrying an MMIC to an external waveguide without the need of a non-planar back metal short, which is normally essential to avoid back scattering from the waveguide and also normally needed to achieve impedance matching. In structures according to the present invention, a patch antenna radiates into the waveguide while the antenna's ground plane reduces back scattering from the waveguide. The one or more capacitive diaphragms provide impedance matching between the microstrip and the waveguide.

Transmission line to waveguide transition including antenna patch and ground ring

A monolithic microwave integrated circuit (MMIC) semiconductor chip, for use with a hybrid coupler, in a frequency downconverter. The chip has a first input lead for receiving a first combined input signal from the coupler, a second input lead for receiving a second combined input signal from the coupler, and an output lead. Each input signal is a microwave signal combined with a further frequency signal, and one of the microwave and further frequency signals of the first combined signal is out of phase with one of the microwave and further frequency signals of the second combined signal. A single balanced mixer has a first single ended mixer for converting the first combined signal to a first intermediate frequency signal and a second single ended mixer for converting the second combined signal to a second intermediate frequency signal. An amplifier is coupled to the first and second mixers for forming an amplified unbalanced intermediate frequency (IF) signal at the output lead representative of the first and second intermediate frequency signals.

Single balanced frequency downconverter for direct broadcast satellite

Growing community of inventors

San Jose, CA, United States of America

Edmar Camargo