Title :
High-efficiency power characteristics for WCDMA applications of SiGe HBT devices using a novel form of base-bias resistance
Author :
Kondo, M. ; Miyashita, I. ; Koshimizu, Masanori ; Kagotoshi, Y. ; Nagai, Hiroto ; Washio, K.
Author_Institution :
Central Res. Lab., Hitachi Ltd., Tokyo, Japan
Abstract :
We present SiGe heterojunction bipolar transistor (HBT) devices that exhibit highly efficient and linear power characteristics comparable to those of GaAs HBTs under wide-band code-division multiple-access (WCDMA) modulation for the first time. Two resistors in series are inserted in the base-bias current path of the device. One only conducts envelope-frequency components of the base current while the other also conducts DC. By adjusting the resistance values, the adjacent channel power ratio (ACPR) was significantly reduced over a wide range of output power levels without loss of efficiency. An optimized device with a total emitter area of 3390 /spl mu/m/sup 2/ exhibited 44% power-added-efficiency (PAE) and 27.3-dBm output power with ACPR of less than -40 dBc under WCDMA modulation at 1.95 GHz and 3.4-V bias voltage.
Keywords :
Ge-Si alloys; UHF bipolar transistors; code division multiple access; heterojunction bipolar transistors; microwave power transistors; power bipolar transistors; resistors; semiconductor materials; 1.95 GHz; 3.4 V; 44 percent; SiGe; SiGe HBT devices; SiGe heterojunction bipolar transistor; WCDMA applications; WCDMA modulation; adjacent channel power ratio; base-bias current path; base-bias resistance; envelope-frequency components; high-efficiency power characteristics; highly efficient linear power characteristics; optimized device; output power level range; power-added-efficiency; resistance value adjustment; series resistors; total emitter area; Gallium arsenide; Germanium silicon alloys; Heterojunction bipolar transistors; Modulation coding; Multiaccess communication; Power generation; Resistors; Silicon germanium; Voltage; Wideband;
Conference_Titel :
Microwave Symposium Digest, 2003 IEEE MTT-S International
Conference_Location :
Philadelphia, PA, USA
Print_ISBN :
0-7803-7695-1
DOI :
10.1109/MWSYM.2003.1210602
