A narrowband low noise amplifier for passive imaging systems

Abstract

The design of a narrowband low noise amplifier (LNA) module at Ka band is presented. A low noise MMIC chip fabricated in GaAs pHEMT process is employed. Since the LNA is narrowband, its matching is sensitive to parasitic associated with the bond-wire interconnects and the fixture connectors. A T-type matching network which comprises of a high-low impedance lines is realized on microstrip substrate to nullify the bond-wires inductance. The planar structures in the design are simulated in ADS Momentum® while the bond-wires are modeled in a FEM based full-wave simulator. The design, assembly and packaging of the module are described. The measured results exhibit 23.5 dB gain at 35 GHz frequency. The 1:2 VSWR bandwidth is 2 GHz. The measured noise figure is 3.5 dB.