A Modular Textile Antenna Design Using Snap-on Buttons for Wearable Applications

An antenna design concept with detachable radiation elements offering modular geometry reconfigurabilities for wearable applications is presented. By utilizing snap-on buttons, both as the radio-frequency (RF) connection and mechanical holding mechanism, different modularly interchangeable microstrip patches are employed to demonstrate geometry reconfigurabilities in terms of polarization and resonance frequency. The uniqueness of the design arises from the fact that all configurations share one common feed structure which consists of a two-layered substrate including snap-on buttons, a ground plane, and a proximity coupled feed. To show the concept, modular realizations with different functionalities in terms of polarization or resonance frequency are demonstrated in this paper. First, a detachable patch offering interchangeable right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) at 5 GHz is proposed. Second, a demonstration of a planar inverted-F antenna (PIFA) concept offering interchangeable resonance frequencies for the 2.4- and 5.3-GHz bands of wireless local area networks (WLAN) is given. Finally, a patch module designed for 8-GHz operation is presented to show the versatility in frequency modularity. Experimental results of the fabricated antennas in free space, worn by a torso phantom and in bending conditions, validate the concept and prove that this type of modular design offers convenient, passive, low cost, and versatile system reconfigurabilities, which can benefit wearable applications.