Design of a 0.5–18 GHz Wideband Switching Matrix Box for Electronic Support Measurement

Abstract

In this paper, we design and fabricate a broadband switching matrix box with low-noise figure, flat gain characteristics, and reliability by applying the chip-and-wire process using a bare-type MMIC device. To compensate for the mismatch among many components, the limiter, switch, amplifier, and power divider, which are suitable for sub-band frequency characteristics, are designed and applied to the matrix box. The matrix box has three submodules that are phase-matched for each frequency band and one built-in test (BIT) submodule to select the BIT path for calibration. Phase-matched RF semi-rigid cables of different lengths are used to connect to the external interface of the matrix box. The main RF line is a dielectric substrate, RT/Duroid 5880, with a relative dielectric constant of 2.2 and a dielectric thickness of 0.127 mm. The BIT path is a dielectric substrate, ceramic alumina (AI₂O₃), which has a relative dielectric constant of 9.8 and a dielectric thickness of 0.254 mm. In the wideband switching matrix box, the gain is from −1.71 dB to −2.69 dB at LB (input frequency, 0.5−2 GHz), with a flatness of 1.0 dB. Th e gain is from +14.8 dB to +12.4 dB at MB (input frequency, 1−6 GHz), with a flatness of 2.4 dB. The gain is from +12.6 dB to +9.4 dB at HB (input frequency, 6−18 GHz), with a flatness of 3.2 dB. The measured values of the noise figure are 2.69 dB at low band, 4.4 dB at medium band, and 5.95 dB at high band with a maximum value. The measured value of phase matching at high band is 7º with a maximum value.