Reconfigurable Wideband RF Impedance Transformer Integrated with an Antenna for Multi-band Wireless Devices

In this paper, we design and implement an ultra wideband antenna using impedance transformer for next generation radio Frequency (RF) front-end. Centre to this, a novel reconfigurable radial stub impedance transformer is proposed to achieve a wideband characteristic for a diverse set of frequency standards. A prototype of the impedance transformer has been fabricated and tested which demonstrates a close match between design simulations and measured results. 4X improvement to the bandwidth and 2X improvement to the return loss are achieved when the proposed impedance transformer is integrated with a narrow bandwidth antenna. The results show that adding the reconfigurable RF transformer can facilitate excellent frequency agility of the return loss of the antenna over other frequency standards. The proposed design technique significantly enhances the system capability to operate with multiple operating frequencies; providing the possibility to realize a reconfigurable RF front-end system.