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A QPSK direct‐conversion receiver for wireless communications
Author(s) -
Karmakar Nemai Chandra
Publication year - 2005
Publication title -
international journal of rf and microwave computer‐aided engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 39
eISSN - 1099-047X
pISSN - 1096-4290
DOI - 10.1002/mmce.20049
Subject(s) - intermodulation , baseband , harmonic mixer , direct conversion receiver , image response , local oscillator , intermediate frequency , electrical engineering , rf front end , radio frequency , phase shift keying , electronic engineering , frequency mixer , physics , radio receiver design , hybrid coupler , amplifier , engineering , power dividers and directional couplers , transmitter , cmos , detector , bit error rate , channel (broadcasting)
The design and development of a compact receiver front‐end comprised of two even‐harmonic direct‐conversion mixers, a quadrature hybrid coupler, two bandpass filters, two lowpass filters and a Wilkinson power divider are presented. The subharmonic mixer utilizes a well‐matched antiparallel diode (APD) pair. The design helps improve the 2 nd ‐order intermodulation performance (IM2) due to the suppression of the even‐order mixing products and LO noises. The receiver front‐end is able to generate in‐phase I and quadrature‐phase Q baseband outputs at 35 MHz. The detailed design of radio frequency (RF) components at the C‐band and a quadrature intermediate frequency (IF) carrier signal in the I and Q waveforms are demonstrated successfully with a 9‐dB effective IF conversion loss at 10‐dBm LO power at the C‐band. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.