Frequency-Reconfigurable Multimode Antenna for Cognitive Radio

Abstract

Background/Objectives: Modern communication devices need a multi standard, and multi functional RF(Radio Frequency) front end to utilize the communication spectrum efficiently.The objective of this paper is to design an electronically tunable frequency reconfigurable MSA(Micro Strip Antenna) operating in dual mode. Methods and Methodology: This paper presents an innovative digitally/electronically controlled frequency-reconfigurable meandered T- slot MSA for frequency reconfiguration in CR(Cognitive Radio) applications. This is designed by incorporating a modifiable slot structure in the radiating patch. The antenna was designed to resonate in dual modes. Both the modes have dual resonant frequency of operation .The frequency agility of the EM (Electro Magnetic) structure was electronically controlled by using RF-PIN diode. Coplanar waveguide (CPW) feeding was selected to allow for the integration of the MSA with (Monolithic Microwave Integrated Circuit) MMIC circuits. Findings: The simulated results for both the operational modes show a return loss for acceptable performance in Cognitive Radio applications (i.e. < -10dB). The meandered arms and side slots of the proposed meandered T-slot MSA are selected using parametric studies to get the desired resonant frequency. The first mode (Mode-1) of resonant frequencies are at Fr=2.56 GHz and Fr=5.8 GHz. The second mode (Mode-2) operating frequencies are at fro= 2.38 and fro=5.63 GHz. The proposed antenna was designed on a smaller PCB footprint of 32*42mm2 to operate in S (2-4GHz) and C (4-8GHz) bands. The Finite element method (FEM) analysis method in ANSYS- High Frequency structure simulator (HFSS) was used for full wave simulation. Frequency ratio of 2.2 and 2.32 was achieved in Mode-1 and Mode-2 respectively.