Title :
A QPSK direct digital modulator in GaAs HBT at 28 GHz
Author :
Sun, Yi ; Freundorfer, A.P. ; Sawatzky, Dave
Author_Institution :
Dept. of Electr. & Comput. Eng., Queen´´s Univ.
Abstract :
A new overlay coupler and power combiner have been realized at millimeter-wave frequency. The coupler and power combiner have an area that is less than one half that of the Lange coupler and two-stage Wilkinson power combiner respectively. They were used to construct a QPSK modulator, employing balanced reflection topology, in which the HBTs acted as switches. The QPSK channel showed plusmn0.4 dB amplitude imbalance and plusmn2deg phase error over 24~32 GHz
Keywords :
III-V semiconductors; bipolar transistor circuits; bipolar transistor switches; gallium arsenide; modulators; power combiners; quadrature phase shift keying; waveguide couplers; 28 GHz; GaAs; HBT; Lange coupler; QPSK; balanced reflection topology; direct digital modulator; millimeter-wave frequency; two-stage Wilkinson power combiner; Binary phase shift keying; Conductors; Coplanar waveguides; Coupling circuits; Digital modulation; Gallium arsenide; Heterojunction bipolar transistors; Power combiners; Quadrature phase shift keying; Reflection;
Conference_Titel :
Electrical and Computer Engineering, 2005. Canadian Conference on
Conference_Location :
Saskatoon, Sask.
Print_ISBN :
0-7803-8885-2
DOI :
10.1109/CCECE.2005.1557349
