A wide-band QPSK modulator using branch-line coupler and MESFET switches

Author

Ghaffar, Farhan A. ; Mobeen, M. Kashan ; Qamar, Sharjeel ; Hasan, Muhammad

Author_Institution

SUPARCO, Pakistan

fYear

2009

fDate

2-5 Aug. 2009

Firstpage

1014

Lastpage

1017

Abstract

This paper reports the design and implementation of microstrip based quadrature phase shift keying (QPSK) modulator using quadrature hybrid (Branchline) coupler and MESFET switches. The modulator is designed to operate between 7.5 GHz to 9.5 GHz. Fabricated modulator has carrier suppression of 29 dB across the frequency range and has an amplitude imbalance of less than 0.1 dB with phase imbalance of 0.4deg around its center frequency. The modulation is checked upto 160 Mbps and spurious suppression is found to be greater then 40 dB and has zero DC power consumption.

Keywords

field effect transistor switches; microstrip couplers; power consumption; quadrature phase shift keying; radio transmitters; MESFET switch; carrier suppression; frequency 7.5 GHz to 9.5 GHz; power consumption; quadrature hybrid (branchline)coupler; quadrature phase shift keying; wide-band QPSK modulator; Amplitude modulation; MESFETs; Microstrip; Phase modulation; Quadrature phase shift keying; Reflection; Signal design; Switches; Topology; Wideband; MESFET; Microstrip; Quadrature Phase Shift Keying (QPSK); Switch;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2009. MWSCAS '09. 52nd IEEE International Midwest Symposium on

Conference_Location

Cancun

ISSN

1548-3746

Print_ISBN

978-1-4244-4479-3

Electronic_ISBN

1548-3746

Type

conf

DOI

10.1109/MWSCAS.2009.5235973

Filename

5235973