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.

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-i-n 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.

In this paper, a compact, wideband, printed antenna is proposed for millimeter-wave fifth-generation communication systems. The proposed design is a patch antenna with a defected ground structure, in which ground plane defects are utilized to reduce resonance and achieve wideband operation. The optimized antenna dimensions are 2.5 mm × 4.5 mm with a substrate thickness of 0.203 mm. A prototype antenna was fabricated and measured to verify the performance, and it was established that the simulated and measured results were in good agreement. The measured bandwidth was approximately 6.4 GHz (26.5–32.9 GHz) with a peak gain of 5.62 dBi and an efficiency in operational bandwidth of 84%. The compactness, wide bandwidth, and decent gain suggest that the proposed antenna is a potential contender for forthcoming communication systems.

A compact size patch antenna resonating at 28GHz is presented in this paper. The antenna is simple in structure and fed using microstrip line which enhances its use with different circuitry. The antenna is designed keeping in mind the specification proposed by European Standard Telecommunications series (ETSI). Proposed antenna shows good results in term of return loss and gain, the antenna also satisfies the Federal communication commission (FCC) proposed bandwidth for 28GHZ i.e. 27.5-28.25GHz. ROGERS RT/Duroid 6002 is used as a substrate of the antenna, while the antenna is simulated using commercially available software Higher Frequency Structural Simulator (HFSS).