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The design and realization of a compact coplanar waveguide (CPW) fed ultrawideband (UWB) antenna having dual‐notched bands is presented in this article. The antenna possesses on demand notch bands at 4 to 5.78 GHz and 6.83 to 8.22 GHz. The presented design consists of a single iterated octagonal patch antenna designed on cheap FR4 substrate. The stub is utilized to achieve a wide impedance matching of 7.33 GHz (3.2‐10.5 GHz), while the notch‐bands are realized using split ring circular slots. These notch‐bands are controlled independently without affecting the overall performance of the antenna. Simulated and measured results showed that the antenna offers excellent performance with an overall size of 20 × 23 mm2, high efficiency of more than 90%, and a nearly omnidirectional maximum gain of 4.8 dBi. The performance of the proposed antenna is better than the antennas presented in the literature in term of size, stable gain, and independently controllable notch bands. Besides these advantages, the compact size allows the antenna to integrate into small devices easily and help manufacturers to produce a massive number of antennas comfortably.

This paper presents a compact frequency reconfigurable antenna for flexible devices and conformal surfaces. The antenna consists of a simple easy to fabricate structure consisting of a stub loaded circular radiator, designed on commercially available RT5880 flexible substrate (εr = 2.2) with a thickness of 0.254 mm. The combination of stub loading and slot etching techniques are utilized to achieve the advantages of compactness, frequency reconfigurability, wide impedance bandwidth, and stable radiation pattern with structural conformability. The frequency reconfigurability is achieved by employing two p-in diodes. Simulated and experimental results showed that the antenna operates in various important commercial bands, such as S-band (2 GHz-4 GHz), Wi-Max (3.5 GHz and 5.8 GHz), Wi-Fi (3.6 GHz, 5 GHz, and 5.9 GHz), 5G sub-6-GHz (3.5 GHz and 4.4 GHz-5 GHz), and ITU-band (7.725 GHz-8.5 GHz) with the additional advantages of structural conformability. Furthermore, the performance comparison of the proposed flexible antenna with the state-of-the-art flexible antennas in terms of compactness, frequency reconfigurability, and number of operating bands demonstrates the novelty of the proposed antenna and its potential application in heterogeneous applications.

This paper presents the design and characterization of a compact broadband antenna and its MIMO configuration for 28 GHz 5G applications. The antenna was designed using Rogers RT/5880 with a thickness of 1.575 mm and has an overall compact size of 30 mm × 30 mm. The design methodology was initiated by designing a compact conventional microstrip antenna for 28 GHz. Afterward, the rectangular slots were utilized to improve the impedance bandwidth so that antenna covers the globally allocated 28 GHz band spectrum for 5G applications. Furthermore, a compact 2 × 2 MIMO antenna with polarization diversity is designed for high channel capacity systems. The mutual coupling between the closely spaced antenna elements is reduced by using two consecutive iterations of defected ground structure (DGS). The proposed MIMO antenna system offers broad bandwidth, high gain, low mutual coupling, and low envelope correlation coefficient along with high diversity gain, low mean effective gain, and low channel capacity loss. Moreover, the proposed been compared with the state-of-the-art MIMO antenna proposed for 28 GHz application to demonstrate worth of the presented design.

A wide-band and tri-band flexible antenna for fifth-generation (5G) sub-6-GHz communication systems is investigated in this paper. The proposed wideband antenna covers the 5G new radio (NR) mid-band, ranging from 2.8 to 5.35 GHz, while the tri-band antenna is resonating at three different allocated frequency bands (2.45 GHz, 3.5 GHz, and 4.7 GHz) for 5G sub-6-GHz communications. This functionality is achieved by introducing hexagonal split-ring resonators in the radiating element, which can be controlled independently without affecting antenna performance to avoid problems of interference in this frequency spectrum. In addition, the antenna also presents a good conformability characteristic, and the simulated results are confirmed with the measurements of the fabricated prototype.