Filtennas for wireless application: A review

Abstract

In recent year, various filtenna circuits have been developed satisfying the objectives and prerequisites of wireless communication. Some of these developed designs are new or some are the improved version of previous works whereas the others are the combination of conventional methods. This article presents the review of filtenna circuits starting from the beginning to the improvements until date. This article starts with brief overview of various filters with their design strategies and ends in its implementation in filtenna designs followed by discussion on several filtenna designs in term of size and overall performances. Among various designs, bandpass, and bandstop filters are extensively used in filtenna realization as it provides a better selectivity in desired band. Various planar filtenna circuits, based on either defected ground structure (DGS) or resonator or SIW filters are reviewed and presented. Besides, planar filtennas, these filters are also integrated to the aperture of horn antennas for the realization of horn filtennas, applicable for high frequency operations. It is observed that SIW based filtennas exhibited narrow impedance bandwidth. This feature can be improved by doubling substrate layer as well as the number of metallic ways. Whereas, resonator based filtennas use resonator based filters along with DGSs to enhance impedance bandwidth as well as minimize mutual coupling and cross‐polar radiation. Apart from single element filtenna, filtenna arrays, and reconfigurable filtennas (including planar and horn reconfigurable filtennas) are presented. This review article may be helpful for beginners working on filtenna circuits and also such a review process is not available in the open literature to the best of author's knowledge.

Frequency Tunable Filtenna Using Defected Ground Structure Filter in the Sub-6 GHZ for Cognitive Radio Applications

“…Therefore, for space minimization, the concept of integrating both the antenna and filter in a single structure appears as a potential solution, and it is known as filter-antenna or filtenna. In the literature, several approaches containing filtennas have been discussed [6][7][8]. Some authors suggested more than one CR antenna designed separately at the same substrate, an antenna for communication and another for sensing [9][10][11].…”

Compact reconfigurable antenna system for spectrum interweaved cognitive radio

“…The filtenna integrates filters into the antenna system. 23 Recently, the reconfigurable band-notch antenna system is gaining the attention of antenna researchers because it aids in minimizing system interference. 24 Such reconfiguration can be made by using different switches like PIN diodes, optically controlled switches, and RF-MEMS.…”

Single‐fed dual wideband filtenna for 4G / 5G mobile applications

“…A dual band circularly polarized DRA is presented in Reference 12 which covers the important operating band (27.5‐28.35 GHz) for future 5G MMW communication systems. In addition, several filtenna designs have been reported in Reference 13 for recent wireless communications. Planar filtenna structures can be formed based on either defected ground structure or resonator or SIW filter.…”