Explore the vast range of titles available.

This study presents an inkjet printed textile antenna realised using a novel fabrication methodology. Conventionally, it is very difficult to inkjet print onto textiles because of surface roughness. This study demonstrates how this can be overcome by developing an interface coated layer which bonds to a standard polyester cotton fabric, creating a smooth surface. A planar dipole antenna has been fabricated, simulated and measured. This study includes DC resistance, RF reflection coefficient results and antenna radiation patterns. Efficiencies of greater than 60% have been achieved with only one layer of conducting ink. The study demonstrates that the interface layer saves considerable time and cost in terms of the number of inkjet layers needed whilst also improving the printing resolution.

In this work, a wideband magneto-electric dipole antenna with circular polarization is introduced, which covers the 2G, 3G, LTE, and 5G frequency bands. In the proposed antenna, a planar dipole antenna with triangular corners, which plays the role of an electric dipole with circular polarization radiation, is mounted on a vertically-oriented cavity, which acts like a magnetic dipole. A Y-shaped probe is used to excite the antenna, which improves the axial ratio (AR) diagram due to its unique geometry. A sample of the proposed antenna is fabricated, and its measurement results are presented. The measurement results show an impedance bandwidth of 81.46% from 2.35 to 5.58 GHz, which covers the entire bandwidth required for 5G applications. Also, the measured 3-dB AR bandwidth extends from 2.26 to 5.58 GHz (84.61%). The measurement results show a relatively stable gain over the whole band, with a maximum gain of 9.91 dB at 4.8 GHz. One of the most significant advantages of the magneto-electric dipole antenna is its high front-to-back ratio (F/B). This advantage is also achieved in the proposed antenna, resulting in a maximum measured F/B of 29.3 dB. The simulated and measured results show a good agreement.

In this paper, the design of Koch Fractal dipole antenna for first, second and third iteration have been presented. The third iteration of Koch Fractal Dipole Antenna shows a total size reduction of 21.25% compared to the basic dipole antenna optimized at the same frequency of 0.92 GHz. The new antenna is proposed based on the structure of the third iterated Koch fractal is designed using Rogers RO3010 substrate with thickness on 1.27 mm. The proposed antenna shows improvement of return loss to -34.57 dB, gain of 1.92 dB, 99% efficiency. The proposed antenna had reduced 17% of length compared to the basic dipole antenna.

In this study, a miniaturized polarization conversion metasurface (PCM) with a cell size of 6×6 mm is utilized to reduce the radar cross-section (RCS) of a circularly polarized antenna array. Each cell circuit of the PCM comprises a pair of folded L-shaped strips with a meander line, which are printed on the surface of the substrate. This configuration demonstrates a polarization rotation (PR) bandwidth of 112% and achieves a high polarization conversion ratio (PCR) of 90%. To confirm the efficacy of the RCS reduction, the PCM is integrated with a circularly polarized 2x2 dipole antenna array. The measured results of the array are in excellent agreement with the simulated data, indicating at least a 5 dB reduction in monostatic RCS for the proposed antenna array. Furthermore, the integration of the PCM does not degrade the radiation performance of the antenna array, confirming the PCM’s suitability for RCS reduction without compromising antenna functionality.

In this study, we propose a novel wideband aperture-coupled magneto-electric (ME) dipole antenna that achieves enhanced bandwidth by simultaneously leveraging ME resonance and aperture-coupled excitation. Building upon the conventional ME dipole architecture, the antenna integrates a pair of horizontal metal patches forming the electric dipole and a pair of vertical metal patches forming the magnetic dipole. A key innovation is the aperture-coupled feeding mechanism, where electromagnetic energy is transferred from a tapered microstrip line to the dipole structure through a slot etched in the ground plane. This design not only excites the characteristic ME resonances effectively but also significantly improves impedance matching, delivering a markedly broader impedance bandwidth. To validate the proposed concept, a prototype antenna was fabricated and experimentally characterized. Measurements show an impedance bandwidth of 84.48% (3.61–8.89 GHz) for S11 ≤ −10 dB and a maximum in-band gain of 7.88 dBi. The antenna also maintains a stable, unidirectional radiation pattern across the operating band, confirming its potential for wideband applications such as 5G wireless communications.

In this paper, the slotted dipole antenna structure is proposed to have four narrowband frequencies with ability to be reconfigured. Narrowband reconfiguration can be achieved by controlling the length of slotted dipole by using switches. The narrowband frequency is to be at 1.8 GHz (GSM), 2.4 GHz (WLAN), 2.6 GHz (4G), and 3.5 GHz (5G) respectively. The longest dipole length produced 1.8 GHz, the second-longest dipole length produced 2.4 GHz, the third-longest dipole length produced 2.6 GHz, while the smallest dipole length produced 3.5 GHz. To maintain the stability of the RF current in the system, sixteen capacitors were used. As well eight inductors were used to isolate the RF current and power supply. The PIN diode was used as a switch to allow the induced current to stop and pass into the slot which means that it can be used to select the desired frequency. Depending on switching configuration, the operating frequency is tuned. Good matching is achieved for all configurations. The simulated result of gain for the four operating is higher than 2 dB while the omnidirectional radiation pattern has been obtained thus makes the proposed antenna suitable for wireless application.

For ultra-high field and frequency (UHF) magnetic resonance imaging (MRI), the associated short wavelengths in biological tissues leads to penetration and homogeneity issues at 10.5 tesla (T) and require antenna transmit arrays for efficiently generated 447 MHz B1+ fields (defined as the transmit radiofrequency (RF) magnetic field generated by RF coils). Previously, we evaluated a 16-channel combined loop + dipole antenna (LD) 10.5 T head array. While the LD array configuration did not achieve the desired B1+ efficiency, it showed an improvement of the specific absorption rate (SAR) efficiency compared to the separate 8-channel loop and separate 8-channel dipole antenna arrays at 10.5 T. Here we compare a 16-channel dipole antenna array with a 16-channel LD array of the same dimensions to evaluate B1+ efficiency, 10 g SAR, and SAR efficiency. The 16-channel dipole antenna array achieved a 24% increase in B1+ efficiency in the electromagnetic simulation and MR experiment compared to the LD array, as measured in the central region of a phantom. Based on the simulation results with a human model, we estimate that a 16-channel dipole antenna array for human brain imaging can increase B1+ efficiency by 15% with similar SAR efficiency compared to a 16-channel LD head array.

An essential point of the technology in the 5th generation (5G) communications is to utilize the available spectrum in high frequencies beyond 20GHz, whose corresponding wavelengths reach a relatively small millimeter magnitude. To cope with the challenge of such short wavelengths, this paper has proposed a printed dipole antenna with a geometric structure that two dipole arms are patched on opposite sides of a FR4 substrate fed by a microstrip line and triangular balun. Simulations have shown that the proposed antenna possesses a relatively effective performance operated at 21.6 ∼ 25.4GHz with a maximum gain of 1.62dB. Additionally, the impact of some geometric parameters, such as the sizes of dipole arms and triangle baluns, are also discussed in this paper.

The mutual coupling issue between two Right Hand Circularly Polarized (RHCP) Magneto-electric (ME) dipole antennas is addressed in this study. To mitigate this issue, a Metasurface Polarization-Rotator (MPR) Wall is employed, resulting in effective minimization of the coupling effects. The innovative antenna design, with high gain, shows promise for 5G applications. It consists of two electric dipole plates with triangular corners positioned at the top, along with two plates acting as magnetic dipoles perpendicular to the ground plane. Additionally, the presence of four plates on the outer periphery of the antenna contributes to the improvement of the circular polarization (CP) performance of the antenna. The feeding structure is configured in a V-shape. Integration of the metasurface polarization-rotator led to a significant reduction in mutual coupling. On average, the mutual coupling is decreased by more than -20.5 dB, reaching impressive values of -45 dB at 2 GHz, -55 dB at 3.1 GHz, and -40 dB at 3.7 GHz when the MPR wall is placed between the ME antennas. The antenna demonstrates promising performance in terms of impedance bandwidth, with a remarkable value of 61.4% for |S111 < [-10dB]. Furthermore, the axial ratio bandwidth for AR < [3 dB] is 63.36%, representing an 11% increase compared to the configuration without the MPR Wall. The maximum right-hand circular polarization gain achieved by the antenna is 9.91 dB at a frequency of 3 GHz. Additionally, the maximum front-to-back ratio (FBR) is 37.6 dB at a frequency of 2.5 GHz. By comparing and analyzing the simulation results for the scenarios with and without the MPR Wall, it becomes evident that the MPR Wall does not significantly affect the parameters of gain, front-to-back ratio, and impedance bandwidth.

ABSTRACT This paper proposes a dipole antenna with broadband characteristics for WLAN application. To achieve a wide operational bandwidth, the defected ground structure (DGS) technique is integrated on the ground. As a result, the percentage of bandwidth is risen from 15% to 28% for simulation. In addition, the miniaturization technique is implemented by using zigzag lines and angled at 90o while Artificial Magnetic Conductor (AMC) surface is utilized to enhance gain for the antenna. The final design, including two elements (array of 1 × 2), witnesses an overall volume of 0.93λ 0 × λ 0 × 0.12λ 0, in which λ 0 is the free-space wavelength at the lowest operating frequency of 4.64 GHz. At −10 dB, the bandwidth impedance is 28% for simulation (4.638–6.172 GHz) while the peak gain accomplishes 10.3 dBi.