Design of Front-End Receiver and Matrix for 2–18 GHz with a Searching and Tracking Function for an ELINT System

Abstract

In this paper, we describe the design and fabrication of a front-end receiver and matrix modules for 2−18 GHz with high gain, good phase matching characteristics, and reliability; this was accomplished by applying a chip-and-wire process using a bare-type monolithic microwave integrated circuit (MMIC) device. To compensate for the mismatch among many sub-modules, a front-end module, matrix module, and built-in test module suitable for sub-band frequency characteristics were designed and applied to the direct receiver. The matrix box used a high-pass filter to remove unwanted low frequencies and a 4-way divider to distribute single input BIT signals. The broadband receiver module had two paths: a phase path and an amplitude path. Phase- and amplitude-matched radio frequency semi-rigid cables of different lengths were used to connect to the internal sub-modules of the matrix receiver. The main RF line was a dielectric substrate, RT/Duroid 5880, with a relative dielectric constant of 2.2 and a dielectric thickness of 0.127 mm. The sizes of the front-end receiver and matrix box were 137 mm × 120 mm × 31 mm and 250 mm × 238 mm × 138 mm, respectively. In the wideband frequency receiver module, the gain was 22.99 dB at mid-band (frequency 2−6 GHz) with a return loss of about 14.76 dB. Th e gain was 23.25 dB at a high band (frequency 6−18 GHz), having a return loss of about 11.63 dB. The peak values of phase matching among the channels for 2–6 GHz were ±3.30°, and the peak values of phase matching among the channels for 6–18 GHz were ±8.24°.