Title of Presentation: Compact Ku-Band T/R Module for Wide-Swath High-Resolution Radar Imaging of Cold Land Processes

Primary (Corresponding) Author: Simon Yueh

Organization of Primary Author: Jet Propulsion Lab

Co-Authors: Constantine Andricos, Yahya Rahmat-Samii

Abstract: The ACT program has developed a Transmit/Receive (T/R) module operating at Ku-band frequencies to enable the use of active electronic scanning phased array antenna for wide swath, high resolution synthetic aperture radar (SAR) imaging of terrestrial snow cover. For the SAR application, the electrical specifications of prime importance are the peak output power of each module and the stability of the receive gain and transmit power over extended periods of time. The T/R module described has an integrated calibrator which compensates for all environmental and time related changes and results in very stable power and amplitude characteristics.

The module was designed to operate over the full frequency range 13 to 18 GHz although only the two frequencies, 13.4 Ghz and 17.2 Ghz, will be used in this SAR radar application. Each channel of the transmit module produces > 4 watts (35 dbm) over the operating bandwidth of 20 Mhz. The stability requirements of

The module was designed using advanced components and packaging techniques to achieve integration of the electronics in a 2 in (5.08 cm) by 6.5 in (16.5 cm) by 1 in (2.45 cm) package. The module size allows 4 T/R modules to feed the 16 x 16 element subarray on an antenna panel. The T/R module contains 4 transmit channels and 8 receive channels (horizontal and vertical polarizations). Each channel contains GaAs mmic amplifiers and a 5-bit phase shifter and a programmable attenuator.

To meet the compact size and maintain isolation between the channels, a two-sided module approach was adapted. The transmit side of the module houses the 4 transmit channels, the control FPGA, and the power regulators and logic circuitry. It also contains the 4-way microstrip power splitter. The 4 dual channel receivers are packaged on the reverse side of the module along with the two power combiners, H&V, and some logic and power conditioning circuits. The broadband 4-channel highly stable T/R Module will be a useful building block for other radar and communication phased array systems operating in this band.