Compact Flexible Asymmetric Coplanar Strip Fed Spiral Antenna

Abstract

A compact flexible spiral antenna with Asymmetric Coplanar Strip (ACS) feed structure is presented in this paper. The proposed antenna is printed on a 50 µm flexible dupont material with dielectric constant (ε_r) 3.5 and loss tangent (tanδ) 0.027. The overall dimension of antenna is 5 mm×11 mm×50 µm. The prototype is fabricated and its performance is verified. The antenna has a measured bandwidth (-10 dB) of 80 MHz, which can cover ISM 2.4 GHz and WLAN bands. To test the flexibility of the antenna, the antenna is simulated in bent configurations of different radii. Flexibility studies reveal that the resonance is in the 2.4 GHz ISM band even after bending. The proposed flexible spiral antenna is intended for use in sensor applications.