| dc.description.abstract | This thesis presents CMOS wideband low noise amplifier (LNA) and receiver (Rx) front-end in tsmcTM 180 nm CMOS technology and X-band mixers in WINTM 0.25 μm GaN/SiC technology. Four chips including C/X bnad wideband LNA, receiver, and two GaN up-conversion mixers were successfully designed, fabricated and verified. The main research topic is to design a wideband receiver using transformer feedback technique to overcome the limitation of low transconductance of (gm) in CMOS process. Meanwhile, the author developed the methodology to improve the isolation of up-converter mixer in radar transmitter.
The bandwidth extension technique applied in LNA was developed by source-drain transformer coupled between the first and second stages. The formula of the transformer with its self-inductance and coupling factor were derived and implemented in LNA. The measurement results show that the LNA achieved a maximum gain (S21) of 15.6 dB, a 3-dB bandwidth of 5.1 – 11.5 GHz, a lowest noise figure of 4.43 dB, a P1dB of -10 ~ -13 dBm and an IIP3 of 0 ~ - 5 dBm, power consumption of 12.5 mW.
The second circuit is a C/X band wideband low-power receiver front end. The receiver consists of a wideband LNA, a wideband balun, a double balanced mixer and a two-stage transimpedance amplifier (TIA). The channel bandwidth is determined by the RC feedback in TIA. The measurement results show the receiver achieved a maximum conversion gain of 31.5 dB, a 3-dB bandwidth of 4.8 – 11 GHz, an LO-to- RF isolation greater than 70 dB, an LO-to-IF isolation greater than 45 dB, and an IF bandwidth of 125 MHz. The P1dB is -25 ~ -32 dBm and the IIP3 is -23.5 ~ -32.5 dBm, power consumption of 21.9 mW, respectively.
The third circuit is an X-band GaN single-balanced (SBM) resistive up-mixer. Two lumped-element Marchand baluns are used in the LO and RF ports for convenient testing and further integration. The measurement results presents a minimum conversion loss of 8.5 dB, a 3-dB bandwidth of 8.5 - 10.8 GHz, an LO to RF isolation of greater than 12.4 dB, an output power of 8.1 dBm, and an IF bandwidth of 1.1 GHz. The P1dB is 12 ~ 22 dBm, power consumption of 0 mW, respectively. The fourth circuit is an X-band GaN up-mixer which adopted a single-ended up-converter mixer cascading a frequency doubler to overcome the isolation problem in conventional SBM. A 5 GHz quarter-wavelength open stub is added in the output of doubler to increase the LO-to-RF isolation. Meanwhile, IF frequency is selected high up to 150 MHz to relax the specification of filter design. The simulations show the receiver achieved a maximum conversion Loss of 4 dB, a 3-dB bandwidth of 9.2 – 11.2 GHz, an LO-to- RF isolation greater than 33.5 dB, and an IF bandwidth of 240 MHz, power consumption of 630 mW, respectively.
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