A novel wideband CDMA receiver

Abstract

This paper presents an even harmonic direct conversion receiver for WCDMA applications. The receiver uses a very low noise LNA to provide the gain and low noise requirements. A subharmonic pumping mixer converts the RF signal to the baseband signal. This cost effeive mixer is well suitedfor DC Ofset and even harmonics suppression. In order fo decrease the receiver size, some techniques such as reduced size branch line coupler and Wilkinson power divider with the lumped elements are used. The simulation results show that the specifications of proposed receiver ful/y s a t i~b the requirements o f the WCDMA receiver.

Numerical Study of Behavioural Sub-Harmonically Pumped Mixer in a Novel Structure

“…First, due to zero IF (WIF = 0), the problem of image is circumvented. Also, there isn't any need to IF high Q filters and subsequent stages after down conversion [1]. On the other hand, the direct conversion topology suffers from some problems that doesn't exist or aren't as serious as heterodyne counterpart.…”

“…In order to prevent DC Offset, some methods like using mixer with high IP2 or high pass filtering after down converting are offered. Another method to prevent DC Offset is the use of Even Harmonic Mixer (EHM) or Sub-harmonically pumped (SHP) mixers with anti parallel diode pair in both I and Q paths [1].…”