Dinesh Yadav

In this article, a simply structured small-size multi stub resonator based flexible monopole wearable antenna is proposed for N77 (3.3–4.2 GHz) and N78 (3.3–3.8 GHz) bands of 5G communication that was design on the RT/Duroid 5880 substrate with a thickness of 20 mil (0.508 mm). The presented antenna configuration comprised of a monopole antenna and a vertically aligned symmetrically loaded multi stub resonator which excite resonant mode at 3.525 GHz for N77 and N78 bands of 5G applications. At the outset, it is fabricated, tested and its performance experimentally verified. It has the measured impedance bandwidth of about 1.3 GHz (3.15–4.45 GHz) and peak gain of 2.37 dBi at 3.475 GHz. Afterward, the presented monopole antenna is investigated by utilizing multi-layer tissue model for specific absorption rate (SAR) evaluation. At 3.5 GHz, the 1 g/10 g SAR values are 0.112/0.073 W/Kg, respectively, which is substantially under typical values. Lastly, the measured performance of the presented monopole wearable antenna is assessed at numerous on-body parts (i.e., wrist, chest, and leg) and diverse bending scenarios for flexibility and conformability analysis. With the small antenna footprint of 30 mm × 16 mm × 0.508 mm (0.35λ₀ × 0.187λ₀ × 0.0059λ₀ at 3.5 GHz), wide bandwidth, low SAR values, flexible and conformal in nature makes it is suitable for modern 5G wearable applications.

In modern wireless communication systems, antennas that support multiple wireless standards, enabling applications such as WLAN, Wi-Fi, WiMAX, C-band, RFID and 5G NR are essential. These multi-band antennas help reduce both system space and cost. This paper presents a multi-frequency broadband circularly polarized patch antenna based on Gielis’s superformula. The multiband characteristics are achieved through a sunflower-inspired multi-ringed patch structure. The antenna is designed on a 59.691 mm × 60.41 mm Rogers RO4003 substrate and utilizes a CPW feed, which enhances the bandwidth from 0.88 to 1.61 GHz (L-band), 2.46–2.60 GHz (S-band), and 4.87–6.49 GHz (C-band). Circular polarization in the C-band is achieved by introducing slots in the ground plane. The proposed design demonstrates operation at central frequencies of 1.06 GHz, 2.56 GHz, and 5.8 GHz. Simulated and measured results of return loss, radiation patterns, and realized gain show good agreement.

In this study, a compact (30 × 30 × 0.508 mm³) 8-port MIMO antenna for unmanned aerial vehicles (UAV), vehicle-to-everything (V2X) and 5G applications is designed, developed, tested and discussed. After a systematic study, an optimal single element of the proposed antenna is chosen from four steps (Step 1, Step 2, Step 3, Step 4). The geometry of the proposed antenna comprises eight circular radiating elements on the top plane of the substrate in which pentagon structure is etched out from each element to resonate it at 5.5 GHz. Stepped rectangular structure is removed from the ground plane underneath of each radiating elements. A dielectric substrate (RT/Duorid (5870 tm)) is used to fabricate the proposed antenna design with following specification: ε_r = 2.33, h = 0.508 mm, loss tangent (tan δ = 0.0012). A unique structure of the proposed antenna geometry exhibits −10 dB wideband bandwidth of 1.32 GHz (5–6.32 GHz) and high isolation (> 30 dB) in entire band. A peak gain of 6.5 dB and 92% radiation efficiency have been achieved. Moreover, good degree of MIMO characteristics such as envelope correlation coefficient (ECC) (< 0.001), diversity gain (DG) (> 9.87 dB), channel capacity loss (CCL) (< 0.04 bits/s/Hz), channel capacity (37.6 bits/s/Hz) and mean effective gain (MEG) (−12 dB < MEG < −3 dB) have also been obtained. The antenna design was simulated through HFSS and fabricated & tested for further validation of results. Simulated results were found in strong concordance of experimental results.

The current study demonstrates a dual and wideband mmWave 4 × 4 port MIMO antenna for 5G and beyond applications. The proposed antenna is derived from a traditional inset-fed rectangular geometry, modified with multiple curved edges on the top plane to produce a large effective aperture and enable significant surface current distribution. Partial ground planes are connected using 45° tilted conducting strips to form a common ground, which enhances surface current distribution and balances power through each port. The antenna exhibits wide bandwidths of 2.3–6.5 GHz at resonant frequencies of 28–38 GHz, respectively. Moreover, the suggested antenna yields more than 21 dB isolation, 8.3 dB peak gain, 92% radiation efficiency, 89% multiplexing efficiency, an ECC of 0.00007, and a channel capacity of 21 bit/s/Hz. To validate the antenna design, the prototype was fabricated on a Rogers RT/Duroid 5880™ substrate, tested, and compared with simulated results, showing good agreement.

This paper presents the design and development of a compact multi-band high-frequency antenna tailored for millimeter-wave applications, particularly within the 6G frequency range. The antenna features a small footprint of 10 × 12 × 1.5 mm² and is designed using advanced electromagnetic simulations in CST Microwave Studio. Fabrication was carried out on an FR4 substrate, selected for its favorable properties at high frequencies. The antenna demonstrates an exceptionally wide impedance bandwidth of approximately 166%, covering a broad frequency range from 9.1 GHz to 100 GHz with a central frequency near 45.45 GHz. It exhibits stable radiation characteristics across the operating band, achieving a peak gain of 7.95dBi and an overall efficiency of 85%. Its miniaturized form factor and broad operational range make it a strong candidate for a wide spectrum of applications, including X-band radar, Ku-band satellite communications, K-band sensing, Ka-band 5G systems, V-band short-range wireless, W-band automotive radar, and future technologies such as 6G and security imaging systems.

In this paper, a small size multistubs resonator based flexible wearable antenna is demonstrated for dual-band operation. The proposed antenna is composed of vertically aligned multistubs resonator, a 50 Ω microstrip feed and a defected ground structure (DGS). This configuration of antenna resonates at 2.4 and 5.8 GHz Industrial, Scientific, and Medical (ISM) sub-6 GHz bands. It has a small footprint of 32 × 17 × 0.508 mm³ (0.256 λ_L × 0.136 λ_L × 0.004 λ_L at f_L = 2.4 GHz), with measured reflection coefficient magnitudes (|S₁₁|) of − 15.81 dB with bandwidth of 280 MHz (2.3–2.58 GHz) and − 33.06 dB with bandwidth of 580 MHz (5.42–6 GHz) at 2.425 and 5.72 GHz, respectively. Moreover, it has bidirectional and omnidirectional radiation features due to DGS with a measured peak gains of 1.317 dBi (2.425 GHz) and 4.759 dBi (5.72 GHz). This study also explored a widespread investigation on a parametric study, specific absorption rate (SAR), diverse bending conditions and its interaction with diverse on-body circumstances (by placement on the chest, hand, and leg). The SAR values are 1.29 W/kg (1 g) and 0.88 W/kg (10 g) at 2.43 GHz whereas at 5.8 GHz, the SAR values are 0.507 W/kg (1 g) and 0.257 W/kg (10 g), which well within SAR safe limits. The antenna adhere the effective robustness, stable performance during bending deformations and on-body scenarios which validated the antenna effectiveness for wearable sub-6 GHz ISM band applications.

This research develops, simulates, fabricates and measured a coplanar waveguide (CPW)-fed multiband multi-mode frequency reconfigurable antenna for 5G wireless communication. The antenna is design on Rogers RT5880 substrate with a dielectric constant of 2.2, a thickness of 0.508 mm, and a loss tangent (tanδ) of 0.0009 and the dimension is 30×28×0.508 mm3. The presented antenna has shown good impedance matching with reflection coefficients ranging from -14.82 to -50.36 dB at different frequencies between 6 GHz to 24 GHz. The presented frequency reconfigurable antenna design includes four PIN diodes, resistors, and inductors, enabling 16 different configurations. The simulated outcomes showed varied S parameter values and gains, demonstrating the antenna's flexibility. Measurements were taken using vector network analyzer (VNA) and anechoic chamber to assess reflection coefficient (|S11|) and gain, confirming the antenna's performance. The antenna's ability to reconfigure dynamically without losing signal integrity makes it suitable for 5G wireless applications. It meets and exceeds the requirements for multiband operation, validated by comprehensive simulations and measurements, showing its potential for wide use.