Filtering antennas: A technical review

Abstract

Filtering antennas or filtennas realize both antennas and filter functions in a single structure with the sole purpose of reducing losses and size in the design of a radio system. This article presents a comprehensive view of various filtennas design techniques and their types, satisfying the requirements of different wireless communication standards. The codesign and synthesis approaches and multilayer structure, slot/slit, and parasitic elements are the frequently used techniques reported in the literature to date for the filtennas design. The codesign and synthesis approaches need an extra filter in the filtenna's design, thus making it more complex. Whereas multilayer, slot, and parasitic elements do not require additional filters, and help the radio design become compact in size. The individual elements, that is, filter and antenna used in the filtenna are designed by cutting slots, stacking, resonators, or metamaterial structures.There are two broad categories of filtennas, namely, planar and nonplanar. Most of the papers covered in this article are planar, whereas, under the non-

Design Challenges and Possible Solutions for 5G SIW MIMO and Phased Array Antennas: A Review

“…As the authors know, no SIW-based MIMO work has been published addressing this design problem. Although one reconfigurable phased array for a 5G mobile terminal has been reported in which two monopoles are fed by SIW [93]. Hence, enough scope is available to explore this topic.…”

“…In order to reduce these losses in modern wireless systems, the filter is embedded with the antenna in one unit, thus, omitting the use of separate filters. Such a system is called filtenna [93]. Although extensive work was done in this area, very few efforts were performed to design a SIW-based MIMO filtenna at sub-6 GHz [53] and phased array filtenna at mmWave band [94].…”

Compact 5G Vivaldi Tapered Slot Filtering Antenna with Enhanced Bandwidth

“…The filtering concept of integrating a filter with an antenna (co-design) or substituting the last resonator of the filter with an antenna (synthesis strategy) was first proposed in [3,4], respectively. Filtering can also be achieved by etching slots or slits and adding parasitic elements to the antenna [5] which helps in reducing its size. However, they may degrade the antenna performance in terms of gain, polarization polarity, and radiation pattern.…”