Fast Hopping Frequency Synthesizer for UWB Cognitive Radio in 0.13 µm SiGe BiCMOS Process

An integrated fast hopping frequency synthesizer for ultra-wideband (UWB) cognitive radio (CR) is presented in this paper. Based on phase-locked loop (PLL) and single-side-band (SSB) mixing architecture, the frequency synthesizer covers 3.1~10.6 GHz band with a step of 528 MHz and a hopping time less than 9.8 ns. Distortion-cancelled I/Q calibration modules and multiplexers with poly-phase filters (PPF) are adopted to calibrate the I/Q imbalance of the SSB mixers and suppress the image spurs. To increase the bandwidth of the PLL and improve its in-band phase noise by reducing the loop division ratio, a quadrupler is introduced to multiply the crystal-oscillator frequency of 66 MHz to the reference frequency of 264 MHz. The proposed frequency synthesizer is designed in Global Foundry 0.13 µm 8HP SiGe BiCMOS process and its die area is 5.65 mm2. The simulation results have shown that the designed fast hopping frequency synthesizer exhibits hopping time < 8 ns, spurs < −40 dBc, phase noise < −103 dBc in band and < −116 dBc/Hz @ 1 MHz offset. Including the output buffers, the total power consume is 525 mW. The proposed fast hopping frequency synthesizer demonstrates a good performance and is suitable to implement in the UWB-based CR system.