A 39/48 GHz Switchless Reconfigurable Low Noise Amplifier Using Common Gate and Coupled-Line-Based Diplexer

This paper presents a switchless dual-band low-noise amplifier (LNA) that can be reconfigured to include n260 (37.40 GHz) and n262 (47.2.48.2 GHz) millimeter-wave (mm-Wave) dual bands. The proposed reconfigurable LNA is designed to separate and isolate two bands, using a common gate and coupled-line-based diplexer for the inter-stage of cascade amplifiers. A common gate amplifier has the advantage of simultaneously selecting the signal path and amplifying the signal power according to a band, using an impedance variation between the gon/offh conditions of gate bias. In addition, the coupled-line-based diplexer can be optimized to exhibit high isolation characteristics between frequencies using high and low-pass characteristics. The designed reconfigurable LNA is fabricated with the 0.15-μm GaAs pHEMT process. With the high frequency (HF) mode, the reconfigurable LNA achieves a measured gain of 19.2 dB at the center frequency, noise figure, and OP1dB of 48 GHz, 4.8 dB, and 6.88 dBm, respectively. In the low frequency (LF) mode, the reconfigurable LNA exhibits a measured gain of 24.8 dB at the center frequency, noise figure, and OP1dB of 39 GHz, 3.9 dB, and 6.80 dBm, respectively. The chip occupies a core area of 3.04 mm2, which consumes 61.4 mW and 64.7 mW in the HF and LF modes, respectively.