Title :
A low voltage W-CDMA polar transmitter with digital envelope path gain compensation
Author :
Chen, Jau-Horng ; Fedorenko, Pavlo ; Kenney, J. Stevenson
Author_Institution :
Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA
fDate :
7/1/2006 12:00:00 AM
Abstract :
This letter presents a polar transmitter using a dual-phase pulsewidth-modulated buck converter with a 50-MHz effective switching frequency. Using a wideband code division multiple access voice signal, the overall system can achieve 52.8% drain efficiency (49.8% power added efficiency) at 24-dBm output power at 836.5MHz with a 3.5-V supply voltage, while passing both adjacent channel leakage power ratio (ACLR1) and alternate channel leakage power (ACLR2) specifications. A digital finite impulse response filter is included in the envelope path to compensate for gain roll-off at higher baseband frequencies. This envelope path compensation allows greater linear bandwidth to be achieved at lower switching frequencies, thus boosting efficiency, and improving ACLR by as much as 8dB. The polar transmitter is characterized over a supply voltage of 2.5-4.5V, making it well suited for battery powered, handheld applications
Keywords :
CMOS analogue integrated circuits; FIR filters; MIMIC; code division multiple access; low-power electronics; power convertors; transmitters; 2.5 to 4.5 V; 50 GHz; 836.5 MHz; CMOS analog integrated circuit; adjacent channel leakage power ratio; alternate channel leakage power; buck converters; digital envelope path gain compensation; digital finite impulse response filter; envelope elimination; envelope restoration; polar transmitter; wideband code division multiple access; Bandwidth; Baseband; Buck converters; Finite impulse response filter; Low voltage; Multiaccess communication; Power generation; Switching frequency; Transmitters; Wideband; Code division multiple access (CDMA); Kahn technique; complementary metal-oxide-semiconductor (CMOS) analog integrated circuit; envelope elimination and restoration (EER); radio frequency (RF) power;
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2006.877127
