Multi-band RF front-end receiver design for reconfigurable radio

Abstract

The objective of this thesis is to design a RF front-end for reconfigurable radio receiver which can work across many wireless and mobile standards. In order to design an effective reconfigurable radio system, a structure with multiple WLAN and Bluetooth is proposed. In this structure, a Zero-IF receiver chain is applied for WLAN standards while Bluetooth chain adopts a low-IFstructure to maintain the performances and maximum hardware share. Depending on the proposed structure, two dual-band RF front-ends consisting of a dual-band LNA and two single balance mixers are designed in CMOS 0.18 $\mum$ and CMOS 0.13 $\mum$ technology. The simulated results of RF front-end is presented and compared with some recently published works. In the first LNA of proposed RF front-end, instead of switching a device in the input matching, the impedance of the matching circuit is changed by a switched output load and a resistive shunt-feedback circuit. Therefore, the multi-band LNA can comply with the required performances of both gain and input matching at 900MHz, 1.8GHz and 5.2GHz frequency band. In second proposed dual-band LNAs, the circuit is design and fabricated in TSMC CMOS 0.18 $\mum$ technologies and uses a switched effective inductance circuit to switch between two operating frequency modes. The measured result is comparative with many narrow band LNAs while proposed LNA occupies a small chip area because of the minimum number of inductors and maximum hardware share. Measurements show that the input return loss is -16 dB and -24 dB at 2.4GHz and 5.2GHz, respectively. Besides, noise figure is maintained at 4.0dB and 2.6dB while the LNA achieves 11.8dB and 16.0dB gains at 2.4GHz and 5.2GHz, respectively.