| 1. |
- Arshad, Farzana, et al.
(författare)
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Compact beam-switchable antenna for mm-wave 5G handheld devices
- 2021
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Ingår i: IET Microwaves, Antennas & Propagation. - : WILEY. - 1751-8725 .- 1751-8733. ; 15:7, s. 778-787
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Tidskriftsartikel (refereegranskat)abstract
- An electronically beam-steerable antenna (BSA) is envisioned. The presented BSA is a possible solution to overthrow the limitations inherent to phased antenna arrays. The design consists of a gap coupling inset feed rectangular patch (driven element) and 3 x 1 passive parasitic patches deployed on both sides of the driven patch. Prototype having 20 x 20 mm dimensions is printed on Rogers(R) RT/duroid(R)5870. Four switches are used to load the reactive impedance on parasitic patches, which in turn, change the phases of surface current on parasitic elements and the driven element. Based on the different ON and OFF configuration of switches in parasitic array elements, the main beam is steered along with different directions. The simulated results show that the design can operate between 26.8 and 30.3 GHz a wide impedance bandwidth |S-11|< -10 dB (12.5%) with a peak gain of 8.9 dBi and wide 3-dB scanning angle that is, -37 degrees to 156 degrees in the azimuth plane. The exhibited performance of BSA with favourable characteristics, such as wideband, adequate gain, wide-angle beam switching, and low profile renders the BSA a good candidate for 5G millimetre wave handheld devices. Moreover, to corroborate the performance, the design is fabricated, and experimental measurements were performed. Congruence is observed between the experimentally measured and computationally simulated results. The simulated results of spherical coverage analysis of BSA with the integration of smartphone form factor are also presented.
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| 2. |
- Bondarik, Alexander, et al.
(författare)
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Gridded parasitic patch stacked microstrip array antenna for 60 GHz band
- 2020
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:8, s. 712-717
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Tidskriftsartikel (refereegranskat)abstract
- An array antenna design based on a gridded parasitic patch stacked microstrip antenna element is presented. The radiating part in the top layer of one antenna element has nine rectangular metal patches placed in a grid with three rows and three columns with a separation of 0.1 mm between the patches. Two means of realising the array are investigated. In a regular 2 × 2 concept, the parasitic patches of individual elements are placed next to each other, forming on the top layer a uniform grid of parasitic patches with six rows and six columns. In an alternative concept named as shared array, neighbouring antenna elements share one row and one column of parasitic patches, forming on the top layer a uniform grid of parasitic patches with five rows and five columns. The antenna arrays are designed for the 60 GHz band. The measured bandwidth is 13.8 GHz for the single antenna, 15.3 GHz for the 2 × 2 array, and 12.4 GHz for the shared array. The measured realised gain at 60 GHz is 6 dBi for the single antenna, 11 dBi for the 2 × 2 array, and 10.5 dBi for the shared array. The measured radiation patterns have good agreement with simulations.
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| 3. |
- Castañer, Manuel Sierra, et al.
(författare)
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Guest editorial : EuCAP2021 special section
- 2022
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 16:6, s. 303-304
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Das, Goutam Kumar, et al.
(författare)
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Gain-enhancement technique for wearable patch antenna using grounded metamaterial
- 2020
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:15, s. 2045-2052
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a metamaterial (MTM)-based high-gain compact-wearable antenna for 2.45 GHz industrial, scientific and medical radio band application has been proposed. To achieve the flexibility of the antenna, textile material felt fabric has been chosen as the substrate of the antenna as well as MTM. An omega (omega) like structure has been taken as MTM unit cell design. High value of permeability is utilised for the gain enhancement of the antenna. In addition, very low specific absorption rate (SAR) is obtained using the MTM which makes the proposed antenna suitable for the biomedical application. The proposed antenna has achieved about 3 dB gain enhancement along with SAR value of 0.405 W/kg (1 g tissue). The design has been optimised and the prototype with the optimised parameter has been fabricated and tested over the semi-solid phantom and human body. Further, the proposed antenna over different type of textile material has also been validated.
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| 5. |
- Fonseca, Nelson J. G., et al.
(författare)
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Compact parallel‐plate waveguide half‐Luneburg geodesic lensin the Ka‐band
- 2020
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Ingår i: IET Microwaves, Antennas & Propagation. - : Wiley-Blackwell. - 1751-8725 .- 1751-8733.
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Tidskriftsartikel (refereegranskat)abstract
- A parallel-plate waveguide half-Luneburg geodesic lens is designed and experimentally validated in the Ka-band. The geodesic lens profile is modulated using spline functions to reduce its height, while the symmetry halving the lens enables reduction of its in-plane dimensions. This design provides high gain, equivalent to that of a full-Luneburg lens, over a reduced angular range of ±20° to ±30° in azimuth. The specific design reported here has a maximum realized gain of 23.3 dBi in measurement, compared with 23.8 dBi for a full-Luneburg lens twice the size of this design. Very wideband operation is demonstrated both in simulations and measurements. This design is of interest for applications having limited space like millimetre-wave systems on board cubesats and small satellites.
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| 6. |
- Ghaderi Aram, Morteza, 1988, et al.
(författare)
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An ultra-wideband compact design for hyperthermia: Open ridged-waveguide antenna
- 2022
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 16:2-3, s. 137-152
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Tidskriftsartikel (refereegranskat)abstract
- Antennas are the building block of radiative hyperthermia (HT) applicators. This study proposes a compact UWB antenna specifically tailored to meet the requirements for deep HT array applicators. The proposed Open Ridged-Waveguide (ORWG) antenna, which is an adaptation of a double-ridged horn antenna, operates over the frequency band of 400-800 MHz. It was experimentally assessed as a single element. The quality metrics considered were reflection coefficient, penetration depth, effective field size (EFS), and mutual coupling. The design shows a 75.5% fractional bandwidth with a reflection coefficient measured to be below -10 dB from 367 up to 820 MHz. The EFS is greater than the physical dimensions of the 3-by-4 cm aperture. The mutual coupling between two adjacent elements in the array, measured in a flat phantom arrangement, is lower than -30 dB throughout the entire band. The antenna's performance was further tested in two deep HT scenarios in order to assess the mutual coupling and focussing abilities while in the array configuration. To this end, phased array applicators consisting of 10 and 16 ORWG antennas were simulated in CST, and the results are presented for a homogeneous cylindrical muscle phantom and a realistic patient model, respectively. The good agreement between the simulated and measured results suggests that the antenna can be successfully used for HT.
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| 7. |
- Sánchez-Cabello, Carlos, et al.
(författare)
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Ka band microstrip fed slot array antenna with PMC packaging
- 2020
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:14, s. 1837-1845
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Tidskriftsartikel (refereegranskat)abstract
- A wideband slot array antenna fed by perfect magnetic conductor (PMC) packaged microstrip lines at 28 GHz frequency range is presented. The slot array is designed with conventional microstrip technology and a PMC layer is used as a packaging solution to stop surface waves, cavity modes or any unwanted field leakage, coupling or radiation from the feeding lines. The PMC is implemented with a periodic metal pin structure. The array is fed by a corporate feed system and a good agreement with experimental results is obtained.
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| 8. |
- Wu, Zhe, et al.
(författare)
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A single-layer high-gain dipole antenna array with a bidirectional radiation pattern based on parallel-strip line
- 2021
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Ingår i: IET Microwaves, Antennas & Propagation. - : WILEY. - 1751-8725 .- 1751-8733. ; 15:3, s. 323-331
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Tidskriftsartikel (refereegranskat)abstract
- A single-layer dipole antenna array with quasi-Yagi configuration has been proposed and demonstrated, which provides a dual radiation pattern with the same sense. This antenna is mainly composed of a substrate-supported parallel strip line (PSL) and several periodic dipole elements. Fed by PSL, dipole elements can be stimulated with a uniform power, forming a linear dipole antenna array. By adjusting the elements separation appropriately, the step phase of array factor can be tuned to achieve the same directivity as the element dipole. When an SubMiniature version A (SMA) coaxial connector is connected at the beginning of PSL, the fundamental mode TEM in the PSL is excited and the radiation electromagnetic wave from the dipole elements is achieved. A taper line between the SMA and PSL can be used to reduce the discontinuity, minimizing the reflection coefficient of the port. According to the theory of classical Yagi antenna, the gain can be further improved by introducing multiple directors, achieving the gain increment of about 3 dBi in the proposed design. Considering 5 GHz frequency band applications (4.85-5.2 GHz), the experimental and simulated results show the proposed antenna array has a working bandwidth (|S11|<=-10dB) from 4.85 to 12 GHz.
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| 9. |
- Xue, Wei, et al.
(författare)
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Statistical analysis of measurement uncertainty in total radiated power of wireless devices in reverberation chamber
- 2020
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:11, s. 1241-1245
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Tidskriftsartikel (refereegranskat)abstract
- Due to the explosive increase of wireless devices, efficient over-the-air testing of such devices is highly desirable. The reverberation chamber (RC) offers efficient and cost-effective means to determine performance metrics of wireless devices, such as total radiated power (TRP). In this study, the distribution of the measured TRP in an RC is analytically derived, based on which the statistics (i.e. mean, variance) of the measured TRP are derived as well. RC measurements have been performed to verify the analytically derived statistics.
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| 10. |
- Zarifi, Davoud, et al.
(författare)
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Design and development of broadband gap waveguide-based 0-dB couplers for Ka-band applications
- 2022
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 16:11, s. 718-724
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Tidskriftsartikel (refereegranskat)abstract
- The design and fabrication of a wideband millimetre-wave 0-dB coupler is proposed in this paper using gap waveguide technology for low-loss and high-power applications in 30-GHz frequency band. To overcome the fabrication challenges in millimetre-wave frequencies, the gap waveguide technique is utilised. Two gap waveguide-based coaxial- and waveguide-fed 0-dB couplers are designed with broadband performance, high return loss, acceptable coupling flatness and high isolation. For verifying the performance of the proposed structures, a prototype of the waveguide-fed 0-dB coupler is manufactured and measured. The measurement results show that the return and insertion losses and the isolation of the fabricated 0-dB coupler is better than 18 dB, 0.5 and 18 dB, respectively, in the specified frequency range from 26.2 to 34 GHz. Moreover, the breakdown power level of the proposed millimetre-wave structures is in kW orders to satisfy the high-power requirements.
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| 11. |
- Zarifi, Davoud, et al.
(författare)
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Design of a dual-CP gap waveguide fed aperture array antenna
- 2023
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Ingår i: IET Microwaves, Antennas and Propagation. - 1751-8725 .- 1751-8733. ; 17:9, s. 723-730
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Tidskriftsartikel (refereegranskat)abstract
- A slot array antenna with dual-circular polarisation (CP) is presented in this paper. To overcome the fabrication and loss challenges in mm-wave frequencies, the gap waveguide technique is utilised. The right and left hand circular polarisation (RHCP and LHCP) radiations are achieved using slots-fed stepped septum polariser on the longitudinal slot arrays. The waveguides and feeding layer are based on ridge gap waveguide. The experimental results demonstrate the |S-11| and axial ratio of proposed antenna array are lower than -10 and 2 dB, respectively over the frequency range of 29.1-31.7 GHz. The proposed antenna exhibits the measured peak gain of 27.2 dBic at 30.2 GHz. The results prove that the proposed array antenna is a brilliant choice for 30 GHz-band applications and could be developed to realise larger dual-polarised planar arrays.
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| 12. |
- Zhang, Tianling, 1981, et al.
(författare)
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Ultra-wideband linearly polarised planar bowtie array antenna with feeding network using dielectric-based inverted microstrip gap waveguide
- 2020
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Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:6, s. 485-490
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Tidskriftsartikel (refereegranskat)abstract
- A tightly coupled bowtie array antenna at a millimetre-wave band is presented in the study. The antenna has a simple structure and exhibits a high performance over an ultra-wide bandwidth. The feeding network is designed by using the dielectricbased inverted microstrip gap waveguide technology in order to have a compact layout. An 8 × 8 planar array is designed and prototyped. The measured results show that the proposed array has achieved an overall bandwidth of 55.7% from 18.7 to 33.15 GHz. The maximum measured gain is 21.8 dBi at 32.5 GHz, and the total antenna efficiency is above 40% through the whole bandwidth.
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