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A Ka-band high-power waveguide wide-slit antenna array with high efficiency and high-power capacity is proposed in this paper. The antenna uses a waveguide vertical transition structure as a part of the feed network, which improves the compactness and power capacity of the antenna. A 2 × 8 antenna array was simulated, fabricated by 3D printed technology, and measured. The measured reflection coefficient is less than −10 dB in the range of 30.4–30.9 GHz, the tested gain at 30.8 GHz is 25.8 dB, and the corresponding aperture efficiency is larger than 80%. This antenna can be applied in high-power millimeter-wave systems. [ABSTRACT FROM AUTHOR]

In this paper, a high-power ultra-wideband radiation system, composed of multiply radiation modules, is developed based on the space-synthesis method. The radiation module mainly consists of a transistorized pulser, a 2 × 2 combined antenna array, and a power divider. To improve the out parameters [the amplitude, the pulse repetition frequency (PRF), and the rise time] of the transistorized pulser based on the Marx circuit, the influence of the traveling wave process on the output pulse must be concerned. Based on the theoretical analysis, the printed circuit board circuit parameters and the circuit structure of the pulser are optimized. To improve the power synthesis efficiency, the pulse jitter characteristic of the pulser is improved by replacing the conventional base triggering mode with the collector voltage ramp triggering mode for the first-stage avalanche transistor in the pulser. The previous optimized antenna array is utilized in this radiation system, which has a better radiation performance in the prescribed aperture area. In addition, based on the gradient microstrip structure, the power divider integrated with the pulser is designed, which has the advantages of wide bandwidth, low loss, and light weight. Experimental results show that the peak effective potential rEp of the radiation system of 20 radiation modules is 221.8 kV, the maximum PRF could reach 10 kHz, and the half-power radiation angles of its radiation field are about 5° in both the E plane and the H plane. More radiation modules could be integrated into the system to achieve a higher electric field in the future. [ABSTRACT FROM AUTHOR]

This communication presents the design of a wideband circularly polarized (CP) antenna array based on sequential rotation (SR) technique that is excited by a substrate integrated coaxial line (SICL) with mature and stable processing technology for millimeter-wave (mm-wave) applications. Initially, the influence of the amplitude and phase errors of the feeding network on the axial ratio of the CP array is analyzed, and the detailed design scheme of the wideband CP array based on SR technology is summarized, which can be used to design SR CP array with wide bandwidth and high polarization purity. Then, an SICL-fed $4 \times 4$ CP array working in the mm-wave band that is composed of two substrate layers and a bonding film layer is designed. The radiation element is processed with a larger chamfering, which can realize elliptically polarized radiation in a broadband range, and the impedance bandwidth is significantly expanded relative to the working state of linearly polarized and CP, which has a significant impact on the final array working bandwidth enhancement. The feeding network and radiation elements are directly connected in the same plane. Finally, the proposed antenna is processed and measured to verify the theory and design scheme in this communication. Over the frequency range of 25.0–34.0 GHz, the measured 1.5 dB axial ratio bandwidth of the fabricated prototype is 30.5%, and the return losses are less than −10 dB. The maximum measured peak gain is 16.5 dBi. [ABSTRACT FROM AUTHOR]

This article presents a novel triband dual-polarized shared-aperture antenna with frequency-selective function for sub-6 GHz base station applications. The proposed antenna is composed of a dual-polarized square loop antenna with two parasitic loops for 2G/3G/4G (1710–2690 MHz) and a differentially fed dual-polarized planar antenna for 5G (3300–3600 and 4800–5000 MHz) base station applications. These two antennas are placed coaxially but different altitudes for saving the installation space. In order to achieve good individual performance for these two antennas in the same aperture without interference or blocking, the lower band (LB) antenna is designed as a frequency-selective surface (FSS) for the nether mid/upper bands (M/UBs) antenna. The measured results show that the proposed antenna achieves a high port isolation (>20 dB) between LB and M/UBs and a −10-dB impedance bandwidth of 50.4% (1.60–2.70 GHz), 14.9% (3.28–3.80 GHz), and 8.6% (4.75–5.18 GHz). To further validate the design concept, an antenna array composed of four LB elements and eight M/UBs elements with the corresponding spacing is fabricated and measured, which demonstrates the application of the triband shared-aperture antenna in array form. [ABSTRACT FROM AUTHOR]

A wideband traveling-wave circularly polarized (CP) antenna printed on a single-layer PCB for millimeter-wave (MM-Wave) applications is presented in this communication. The proposed antenna radiates the CP wave on the basis of the principle similar to the classical endfire-mode helical antenna. The proposed antenna is terminated with an absorber to realize traveling-wave radiation. The traveling-wave working mechanism causes the proposed antenna to have a frequency scanning function and higher stability compared with resonant antennas. Curved microstrip transmission lines are adopted as the CP radiation elements; the whole array antenna is etched on a single-layer substrate. A prototype operating at 30 GHz is fabricated and measured. The radiation beam of the proposed antenna scans from − 14.5° (28 GHz) to +22.5° (34 GHz), the axial ratios are lower than 3 dB, and the measured gains show a maximum value of 21.9 dBi at 33 GHz and a minimum value of 20.3 dBi at 28 GHz. The measured $| \text {S}_{11} |$ and $| \text {S}_{21} |$ are lower than −10 and −16 dB, respectively, in the frequencies mentioned above. [ABSTRACT FROM AUTHOR]

This communication presents a dual-polarized series-fed array antenna with 30° beam-pointing for millimeter-wave (MM-Wave) applications. The 45° and −45° polarized subarrays share the aperture in an interdigital shape. The spacing between subarrays with the same polarization orientation is set to $0.56\lambda _{0}$ through the use of narrower T-type folded substrate integrated waveguide (TFSIW) instead of substrate integrated waveguide (SIW). The substrate integrated coaxial line (SICL) is adopted to design the array feeding network. To validate the proposed design, a $4 \times 6$ (single polarization) dual-polarized array antenna operating at 28 GHz with 30° beam-pointing is fabricated. Based on the measurement, the return losses are lower than −10 dB from 27.5 to 28.5 GHz, the isolations between the two polarization ports are higher than 30.0 dB in the frequencies mentioned above, the maximum gain at the center frequency is 15.7 dBi, and the cross-polarization levels are lower than −18.5 dB. The proposed antenna only needs one-step processing with the standard PCB technology without additional stitching assembly. Simulated and measured results of the proposed antennas were compared. [ABSTRACT FROM AUTHOR]

This letter presents an omnidirectional printed dipole antenna array with a wide bandwidth. The array is composed of four dipole units etched on a thin substrate, which is simple in structure and easy to be processed. By modifying the triangle-shaped radiation dipole units and gradually increasing the width of microstrip feeding transmission line, the performance of the dipole antenna array is greatly improved. Simulation results show that this omnidirectional antenna has a peak gain greater than 7.39 dBi, and the impedance bandwidth is 16% (VSWR < 1.6), ranging from 2.3 to 2.7 GHz. [ABSTRACT FROM AUTHOR]

The optimization of the sparse time-modulated optimized frequency offset frequency diverse array (S-TMOFO-FDA) with time-invariant spatial-focusing beampattern is presented. The minimum array with smallest number of elements is obtained through iterative optimization. From numerical results, the S-TMOFO-FDA can provide above 70% reduction in the element amount while displaying superior sidelobe performance than the same aperture-sized full uniform time-modulated logarithmically increasing frequency offset frequency diverse arrays. Furthermore, the scanning performance of the optimized array is also investigated. The S-TMOFO-FDAs of different array length are optimized. [ABSTRACT FROM AUTHOR]

In this article, one wideband circularly polarized microstrip antenna array has been proposed and investigated. The technique of sequential rotation subarray has been employed to construct the whole antenna array, which enhances the impedance bandwidth and axial ratio (AR) bandwidth by 54.65 and 220.93%, respectively, when compared with the traditional way of CP array formation. One 8 × 4 antenna array has been fabricated and measured, agreement can be observed between the experimental and simulation results, the measured VSWR bandwidth is 7.33%, the AR bandwidth is 4.31%, and the gain is about 19 dB. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1624–1627, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24438 [ABSTRACT FROM AUTHOR]

Distinguished from conventional inductive or resonant method, this paper presents a novel high radiation gain and narrower half-power beamwidth microstrip patch antenna (MPA) array loading with modified-I-shaped(MIS) electromagnetic metamaterials(MTM) to apply in the microwave wireless power transmission(MWPT). The MIS MTM unit cell is simulated in HFSS and the effective parameters of the meta-atom is extracted by homogenization retrieval method. Detailed single MPA numerical computing and modeled simulation is proposed step by step and optimetrics procedure in HFSS is conducted to optimize the design parameters for optimum performance. To better take advantages of the higher directive radiation gain and planer structure, a 6 × 10 × 1 MIS MTM array acting as superstrate is placed above a 2 × 2 MPA array with delicate feeding network and power distribution system. Experiment investigation indicates that the MPA array with superstrate obtained the peak value gain of 17.66 dB compared to original 13.18 dB in the operating frequency of 10 GHz. The half-power beamwidth decreased from 36.775° to 18.645° for the E-plane and reduced to 19.958° from 38.649° for the H-plane respectively. The measured results of the fabricated prototype are consistent with the simulation ones with slight discrepancy. This method offers valuable guidance for designing high efficiency transmitting antenna system in application of MWPT. [ABSTRACT FROM AUTHOR]