A folded RF front-end with low power techniques and reconfigurable LNA for multiband applications

Abstract

As expanding the wireless communication industries and increasing the available frequency band, various standards are introduced. The market demands for wireless communication systems also are increasing. Among these demands, low power and high integration requirements and multi standard operation requirement have been increasing remarkably. For meeting these two demands, the low power RF front-end and multiband reconfigurable LNA are proposed, respectively. With an increment of portable system, battery life is important issue for system design. The first part of the thesis, I proposed folded RF front-end with low power techniques. The low power RF front-end is designed in TSMC 0.18 um process for 2.4 GHz ISM band direct conversion. Folded mixer, fully differential low noise amplifier (LNA), and inter-stage matching network constitute the proposed RF front-end. Gilbert-cell mixers using the folded technique and current reused LNA have been designed for low power consumption. The proposed RF front-end consumes 7.34 mW from 1.2 V supply voltage, while conversion gain of 23 dB is achieved. In the second part, the reconfigurable LNA with LC series network and capacitor array is proposed to achieve multiband operation. In the input matching network, selection of the operation frequency mode is obtained by switching bias condition of drive stage of LNA and using capacitor array. In output matching network switched inductor and capacitor arrays make the LNA operate in multiband. As a result, the designed LNA operates in triple band: 2.4 GHz, 5.25 GHz, and 5.75 GHz. The reconfigurable LNA is implemented in TSMC 0.18um CMOS process. Within its operation frequency, gains are more than 12 dB while NFs are kept less than 2.3 dB.