This thesis work is concerned with the design and performance analysis of purely textile antenna for wireless applications. The materials used for radiating element, ground plane and dielectric substrate are purely textile. Two types of antennas are studied, the microstrip patch antenna and RFID tag antenna. Each type of antenna is designed and fabricated using two different conductive textile materials as radiating element.  The radiating element and ground plane of conventional printed antenna is manufactured with the metal plating on a solid dielectric substrate. The radiating element which is used in this thesis work has different characteristics as compared to printed antenna because it is made of conductive textile material which is less conductive than metal and elastic in nature. Each conductive textile material has different surface resistivity. The study has been made to analyze the effect on gain and radiation efficiency of the antenna when different conductive textile material is used as the radiating element. The measured results of the fabricated antennas present the full potential of conductive textile materials to be used as an antenna.

To investigate the integration of a textile antenna into a woven substrate at the point of production. The antenna was to have the characteristics of a conventional fabric interms of the handle and drape.

Reconfigurable radio frequency (RF) devices are attractive for miniaturization of wireless components and systems by handling functionality of multiple distinct devices. Existing reconfiguration techniques rely on device loadings with semiconductor diodes, ferrite/ferroelectric materials, and microelectromechanical system (MEMS) switches and capacitors. However, it is well-recognized that these techniques cannot fully address important system metrics such as high efficiency, wide frequency tuning range, high power handling capability and cost. Therefore, novel alternative techniques are highly desirable to advance the state of the art in reconfigurable RF devices. The aim of this dissertation is to investigate the novel concept of microfluidically loaded reconfigurability within the context of RF antennas and imaging systems. The proposed devices operate based on continuously movable microfluidic loads consisting of metal (liquid/solid) and dielectric solutions. Microfluidics and microfabrication techniques are utilized with flexible/rigid multilayered substrates to maximize the reconfigurable loading effect on the devices and enable highly reconfigurable antennas and imaging array realizations. Specifically, a wideband frequency tunable monopole antenna is introduced by utilizing continuously movable liquid metal within the microfluidic channel as a length varying conductor. By resorting to ultra-thin channel walls, the liquid metal volume overlapping with the microstrip line feed is utilized as a non-radiating capacitive excitation point to achieve the realized 4:1 (1.29GHz – 5.17GHz) frequency tuning range. Subsequently, an alternative design that replaces liquid metal volume with a microfluidically movable metallized plate is introduced. This novel liquid-metal-free implementation alleviates the liquid metal associated drawbacks of reliability, long-term device operation, and efficiency. The antenna is shown to provide 2:1 (1.6GHz – 3.5GHz) frequency tuning range with > 87 % radiation efficient. Due to the high radiation efficiency, the antenna is also capable of handling 15 W of RF power which is 10 W more than its liquid metal counterpart. This metallized plate approach is also suitable for reconfiguration of miniature antennas, and this is demonstrated with the design/implementation of a microfluidically reconfigurable top loaded monopole antenna. It is also suitable for reconfiguration of other structures such as textile antennas – and this is demonstrated with a 0.8GHz to 1.4GHz frequency reconfigurable textile antenna realization. The last section of the dissertation introduces a novel surface imaging array realization by utilizing the microfluidically reconfigurable metallized plate as an RF read-out circuit component. Specifically, a 24 element imaging array is designed and validated to operate within 6 – 12 GHz band with subwavelength resonators to demonstrate the possibility of constructing low-cost high-resolution microwave surface imaging arrays by utilizing the microfluidics based reconfiguration techniques. The presented work emphasizes system level implementation of the proposed devices by integrating them with micropump units, controller boards, and investigating their reliability performances under higher power RF excitations.

The thesis is aimed to design textile antennas that can operate in the ISM band 5.8 GHz. Attention is turned to practical exploitation of these antennas under regular conditions. Variations of the bandwidth of the antenna due to washing and waterproofing will be observed. Finally, the impact of the proximity of living tissue on the parameters of antennas will be studied.