University of Texas System

Texas State University

Karl David Stephan

John Anthony Pearce

Tatsuo Itoh

A system and method for remotely measuring the temperature of an object using microwave radiometry that may be used in hostile environments. A single pole-single throw reflective PIN diode switch is operable in a PASS mode and a BLOCK mode. In the PASS mode, the switch passes the power received from the object to a low-noise block converter ('LNB') for amplification. In the BLOCK mode, the switch blocks the object power and reflects the load noise power of an ambient temperature load to the LNB. A detector diode detects the amplified power output during both the BLOCK and PASS mode and the AC signal from the detector is converted to an output signal proportional to the difference in the noise powers detected in the PASS and BLOCK modes. A servo loop uses the output signal to generate a feedback signal to a noise injection diode that causes the diode to inject sufficient power into the LNB to automatically maintain a balance between noise power measured in the PASS mode and the combined noise powers measured in the BLOCK mode. The output signal is then used to compute the temperature of the object.

Remote temperature measuring system for hostile industrial environments using microwave radiometry

An integrated planar antenna-mixer device for microwave reception utilizes a slot-ring antenna and a diode quad connected thereto. The device comprises a planar metallic sheet backed on one side by a dielectric layer. A circular ring pattern is cut from the metallic sheet forming a slot ring antenna with a central disc and a surrounding ground plane. Diodes of a diode quad are connected between the central disc and the ground plane with adjacent diodes being separated by 90.degree.. The incoming microwave signal is directed perpendicular to the device plane and polarized in a direction orthogonal to a local oscillator signal similarly directed. Operation is quasi-optical without waveguides.

Growing community of inventors

San Marcos, TX, United States of America

Karl David Stephan