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:
Jan. 14, 1992
Filed:
Dec. 11, 1990
Liam M Devlin, Horley, GB;
Brian J Minnis, Crawley, GB;
U.S. Philips Corp., New York, NY (US);
Abstract
A variable bi-phase modulator circuit for microwave signals includes a quadrature power divider (1) having signal input and output ports (2 and 3) and two control ports (4 and 5), and two variable resistors each having an input port (11). Each of the two variable resistors includes first and second microwave field-effect transistors (F1 and F2), the drains of which are coupled together via an intermediate resistor (R). These resistors can be formed using microwave monolithic integrated circuit technology and can have very good impedance characteristics. The input port (11) of the variable resistor has a connection to the intermediate resistor (R) and to the drain of the first transistor (F2). Each transistor is connected with zero dc bias between its source and drain and has a channel resistance which changes with change in gate voltage (VG1, VG2). A shunt stub (L1, L2) is connected to the drain of each transistor (F1, F2) to at least partially compensate at the frequency of operation of the transistor for the source to drain capacitance and for shifts in reference plane due to changes in the gate voltage of each transistor.