| dc.description.abstract | This thesis describes the RF front-end receiver for Ka-Band applications which are implemented in WIN 0.15-μm pHEMT and TSMC 0.18-μm CMOS technologies. The implemented circuits include Ka-Band CPW LNA, Ku-Band gm-boosted Colpitts VCO, Ku-Band bias-level shifting VCO, K-Band with compared UNII-Band low voltage operation VCOs, K-Band admittance-transforming VCO, and Ka-Band current-bleeding double balanced Gilbert mixer.
The Ka-Band CPW LNA is presented in the first section. The performance of the circuit may be varied by the variation of substrate thickness. However, this can be released by using CPW transmission line. Moreover, CPW transmission line lets the components of the circuit directly connect to the ground, avoiding the degradation caused by the unnecessary metal runners. The designed CPW LNA achieves the power gain of 13.9 dB, noise figure of 4.3 dB, input/output return losses of 8.5 dB, and 14.6 dB. The input 1 dB power gain compression point (P1dB) and the input third-order interception point (IIP3) occur at -3 dBm and 7 dBm, respectively. The total power consumption is 157.5mW.
Four types of VCO are demonstrated in the second section. The former two types are indirectly applied for the mixer, needed to be series connected with the frequency doubler which doubling the output frequency. The frequency-doubled signal provided for mixer enables the frequency conversion. The first design is Ku-Band gm-boosting Colpitts VCO. By using the gm-boosting technique, the difficulty of the start-up condition in the conventional Colpitts oscillator can be relaxed. This design achieves the central frequency of 13.72 GHz, the tuning range of 812 MHz, and the output power range is from -6 to -3.6 dBm. The achieved FoM is -190.2 dBc/Hz which is calculated from the phase noise of -118 dBc/Hz at 1 MHz offset and the core power consumption of 4.1 mW. The second design is Ku-Band bias-level shifting VCO, letting the transistor working mostly in the saturation region by using bias-level shifting technique. This design achieves the central frequency of 11.9 GHz, the tuning range of 656 MHz, and the output power is the range of -2.3 dBm ~ -0.4 dBm. The FoM is high as -185.7 dBc/Hz which is calculated from the phase noise of -111 dBc/Hz at 1 MHz offset and the core power consumption of 4.5 mW.
The latter two type VCOs are directly applied for the mixer. The K-Band low-voltage operation VCOs with the drain-source coupled transformer are proposed for UNII band applications. The K-Band design achieves the central frequency of 22.85 GHz, the tuning range of 700 MHz, and the output power range from -9.1 to -7.1 dBm. The FoM is high as -187.02 dBc/Hz which is calculated from the phase noise of -104.3 dBc/Hz at 1 MHz offset and the core power consumption of 2.74 mW. Another UNII-Band VCO design achieves the central frequency of 5.08 GHz, the tuning range of 280 MHz, and the output power range from -3.1 to -0.6 dBm. The FoM is high as -185.03dBc/Hz which is calculated from the phase noise of -114.18dBc/Hz at 1 MHz offset and the core power consumption of 2.1 mW. The K-Band admittance-transforming VCO is presented. By this technique, the conventional capacitance varactor is transforming to the variable inductance and also releases the high-frequency loss from of the varactor. This design achieves the central frequency of 25.78 GHz, the tuning range of 290 MHz, and the range of the output power from -5.05 to -2.75 dBm. The FoM is high as -183.2 dBc/Hz, which is calculated from the phase noise of --103.4 dBc/Hz at 1 MHz offset and the core power consumption of 7.8 mW.
The Ka-Band current-bleeding double balanced Gilbert mixer is presented in the last section. The frequencies of LO and IF are selected at 25.6 GHz and 2.4 GHz, respectively. By using the current-bleeding technique, the current through the LO stage is reduced, keeping fast switching on and off of the LO stage transistor. And the input RF signal is still amplified before mixed with LO due to the constant current through RF stage. The measured RF and IF return losses are around 10 dB. The optimized power of LO drive is 2 dBm which result in a maximum conversion gain of 5.2 dB. The 3-dB bandwidths of RF and IF are high as 6.6 GHz and 1 GHz, respectively. The P1dB and IIP3 are -5 dBm and +4 dBm, respectively. The port to port isolations of RF-LO, LO-IF and RF-IF are better than 30 dB. | en_US |