Low‐cost mechanism to reconfigure the operating frequency band of a Vivaldi antenna for cognitive radio and spectrum monitoring applications

Abstract

A frequency agile Vivaldi antenna whose operating frequency band can be switched between two selected bands is proposed in this study for spectrum monitoring and cognitive radio applications. A radiofrequency (RF) switch is introduced into the back-slot of a Vivaldi antenna to allow switching of the operational band. The realised gains of the antenna are 10.5 dBi in the low band around 3.1 GHz, and 12 dBi in high band around 4.1 GHz. The radiation pattern is stable and its direction is consistent across the two bands. This design can be applied to multiple reconfigurable bands by using more RF switches to tune the desired operating frequency. A set of reliable design equations has been provided as well. This reconfigurable antenna offers improved gain and isolation over multiple, wideband and multiband antennas without increasing the cost and size when compared with those designs reported.

Performance Limits of Fluid Antenna Systems

“…We consider a FAS with linear space of W λ where λ is the wavelength, as shown in Figure 1. It is a single-antenna system where the antenna is mechanically flexible, using technologies such as microfluidic systems [5]- [7] or on-off pixels [9], and can be switched to one of the N preset locations along the space. 1 We refer to the location as port, and the ports are evenly distributed over the space of W λ, sharing one RF chain.…”

Fluid Antenna System for 6G: When Bruce Lee Inspires Wireless Communications

“…A very rich literature exists for liquid-metal based antennas, see [3]. Fluid antennas using conductive fluids or liquid metals for different reconfigurabilities have also been actively researched in recent years, e.g., [4,5,[10][11][12]. There is also an interesting idea to use pixel-like electronic switches for designing reconfigurable antennas and such an idea could be an alternative version of "fluid" antenna [13].…”

“…The term “fluid antenna” was first used in [2 ] when distilled water and chemicals were studied as potential materials for an antenna, but reconfigurable fluid antennas emerged only in recent years. There has been an upsurge of research for liquid‐based antennas using liquid metals or ionised solutions for various reconfigurability, e.g., [3–5 ]. They all fall into the category of this new form of antennas.…”

Liquid Metal Bandwidth-Reconfigurable Antenna

“…The literature contains a number of designs for antennas that can be reconfigured between UWB/wideband and narrowband performance. However, most of those designs [6][7][8][9][10][11][12] provide an omni-directional radiation pattern within both modes of operation. The geometry of many of the designs is complex [7], [8], [11].…”