Variable microwave attenuator

Abstract

Abstract A BROADBAND MICROWAVE ATTENUATOR IS FORMED BY CONNECTING A PLURALITY OF PIN DIODES IN A MODIFIED T NETWORK. FOUR SEMICONDUCTOR CHIPS OF PIN DIODE MATERIAL ARE ARRANGED IN A FLAT LAYER SANDWICHED BETWEEN CONDUCTORS TO FORM A STRIP-LINE CONFIGURATION OF A TEM TRANSMISSION LINE, WHEREBY THE DIODES ARE PART OF THE LINE. THIS STRIP-LINE CONSTRUCTION IS USED WITH OUTER DIODES CONNECTED IN SERIES CIRCUIT RELATION BETWEEN INPUT AND OUTPUT TERMINALS, AND INNER DIODES IN SHUNT RELATION TO GROUND TO FORM THE T NETWORK. THE DIODES ARE CONSTRUCTED AS SILICON CHIPS AND ARE MOUNTED IN VERY CLOSED RELATION WITH A SUBSTANTIALLY UNIFORM CONDUCTIVE STRIP FORMING THE SERIESCIRCUIT CONNECTION BETWEEN THE CENTRAL DIODES AND OF A LENGTH WHICH IS SMALL COMPARED TO THE WAVELENGTH AT HIGH FREQUENCIES. THEREBY, THIS CONNECTION IS SUBSTANTIALLY LOSSLESS AT LOW FREQUENCIES, AND MAINTAINS THE CHARACTERISTIC IMPEDANCE OF THE LINE AT HIGH OPERATING FREQUENCIES. BIAS SIGNALS ARE SUPPLIED TO THE OUTER AND INNER DIODES VIA CONICALLY SPIRAL RESISTIVE CONDUCTOR THAT FORM BROADBAND, REFLECTIONLES, NON-ABSORBING CONNECTIONS. THE CONICAL SPIRAL CONDUCTOR SERIES AS A SINGLE-WIRE TRANSMISSION LINE HAVING A HIGH IMPEDANCE TO HIGH-FREQUENCY SIGNALS OVER A BROAD BAND CARRIED BY AN R-F TRANSMISSION SIGNALS OVER A BROAD EFFECTIVE COUPLING TO SUCH AN R-F LINE.

Inventors

• 👤 S Hopfer

Bibliographic Details