Table of Contents
Advances in Electrical Engineering
Volume 2014, Article ID 593194, 10 pages
Research Article

Design of Tunable Monopole Arm Planar Spiral Antenna for Cognitive Radio

Department of Electronics and Telecommunication, University of Mumbai, Santacruz East, Mumbai 400032, India

Received 23 April 2014; Revised 4 July 2014; Accepted 9 July 2014; Published 24 July 2014

Academic Editor: Sarod Yatawatta

Copyright © 2014 Rahul Yadav. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents a spiral antenna design operating in the frequency range of 1–15 GHz having both selective notch bands and wideband response. The main feed arm of spiral antenna is configured as rectangular monopole of width quarter wavelength to achieve impedance matching with standard 50 Ω excitation. Frequency tuning in the design is achieved by placing varactor diode at an appropriate position along the spiral arms and in the ground plane. The design offers a peak gain of 3.4 dB (simulated) and 3 dB (measured). The unique frequency response of antenna makes its suitable to be used for front-end system of cognitive radio for sensing the spectrum in various modes.