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In this article, a concept of partial structure reuse is presented, and on this basis, a 3.5/28 GHz shared-aperture antenna supporting 2-D (endfire and broadside) steerable beams in the millimeter-wave (MMW) band is developed. The antenna consists of a 3.5 GHz planar inverted-F antenna (PIFA) and two 1 $\times $ 6 28 GHz substrate-integrated DRA (SIDRA) beam-steerable arrays, in which partial structures of the PIFA are reused by the two MMW arrays. To improve the performance of PIFA, two narrow slots and one lumped capacitor are introduced to reduce its H-plane cross-polarization and enhance the operating bandwidth, respectively. To verify the design, antenna prototypes were fabricated and measured. Measured results show that the antenna can cover a dual-band of 3.28–3.67 (11.2%) and 26–29.7 (13.2%) for the endfire and 25.9–29.7 GHz (13.8%) for the broadside. The peak gains of 4.8 and 10 (endfire) and 10.8 dBi (broadside) are obtained by the MW element and two 1 $\times $ 4 MMW arrays, respectively. Each of the MMW arrays can steer the beams from − 50° to + 50°, covering different parts of the space. The shared-aperture antenna has a compact size of 0.45 $\times $ 0.3 $\times \,\,0.03\lambda _{01}^{3}$ ($\lambda _{01}$ is the free-space wavelength at 3.5 GHz), making it suitable for terminal applications. [ABSTRACT FROM AUTHOR]

A high-efficiency dual-band dielectric filtering antenna based on three parallel placed dense dielectric strip resonators (DDSRs) is proposed for the self-filtering property. That means both the filtering responses of the two bands are only determined by the three DDSRs themselves without extra filtering circuits. The even-mode coupling of the TM1δ mode (TM3δ mode) between the middle and two-sided DDSRs is used to form the first (second) radiation band, while the odd-mode coupling contributes one radiation null at the upper edge of each radiation band. Therefore, the proposed dual-band dielectric antenna exhibits relatively high total efficiency benefited from the self-filtering characteristic. Additionally, the presented one without extra filtering circuits obtains the features of low profile, enhanced bandwidth, and gain. For test and verify, a prototype was measured at 7.7 and 13.35 GHz with the fractional bandwidths of 11.4% and 4.8%, the peak gains of 7.65 and 10.5 dBi, and the total efficiencies of 89% and 87%, respectively. Radiation nulls are generated at 8.5 and 13.8 GHz, respectively. [ABSTRACT FROM AUTHOR]

A novel pattern-reconfigurable dielectric resonator (DR) antenna with endfire beam-scanning feature is proposed in this letter. The proposed antenna consists of a DR, a switchable director with 10 p-i-n diodes, and a differential feeding structure. The differential-fed DR operating in TE01δ mode can provide a primary endfire pattern with wide beam. Based on this, a large-coverage beam-scanning performance can be obtained by introducing a switchable director placed in front of the DR. A prototype is fabricated and measured to verify the proposed design. By switching the p-i-n diodes of the switchable director, the proposed antenna enables a near-continuous beam scanning from −48° to +48° in the azimuth plane with a gain fluctuation of less than 0.5 dB. Besides, the 3 dB scanning coverage is up to 164° (from −82° to +82°), which shows good beam-scanning performance. [ABSTRACT FROM AUTHOR]

This letter presents a simple and effective self-decoupling method for dielectric patch (DP) antenna (DPA) by choosing proper structural parameters, without adding extra components. By theoretical analysis, the attenuation constant of the employed fundamental TM01 mode outside the DP is controlled by the structural parameters of the DP resonator, which is crucial for the decoupling between the two adjacent DPAs. It is found that the larger the attenuation constant of the TM01 mode, the better the port-to-port isolation in broadband, and then the radiation pattern can be stabilized. Under the premise of satisfactory isolation, the operational bandwidth and boresight gain of the DPA are studied for ensuring good antenna performance, exhibiting high design freedom and flexibility of the DPA. For demonstration, 1 × 2 closely spaced DPAs with optimal parameters are fabricated and measured. The simulated and measured results show good agreement. [ABSTRACT FROM AUTHOR]

The shared aperture antenna is regarded as one of the promising approaches to support new frequencies with very efficient space utilization. To the best of the authors’ knowledge, there are few shared aperture antennas that include both the sub-6 GHz antenna and the millimeter-wave (mm-wave) beam-steering array for broadside applications. In this article, a broadside sharing aperture technique is developed so that a 2 $\times4\,\,26$ GHz beam-steering substrate-integrated DRA (SIDRA) array can be integrated into a 3.5 GHz bandwidth enhanced perforated patch antenna in a coplanar and aperture-shared way. The proposed solution benefits from several aspects. First, the 3.5 GHz antenna features a compact size as this part is built on the substrate (where the mm-wave SIDRA is constructed) with a high permittivity. Second, the mm-wave SIDRA is a 3-D-type device, and in the case of coplanar integration, its height can be freely adapted to the thickness of 3.5 GHz antenna without concerning the impact from surface waves as many 2-D-type antennas have to do. Third, the antenna can be implemented with the multi-layer printed circuit board (PCB) process, yielding a high integrity level. The dual-frequency antenna was designed, fabricated, and measured. The performances of the antenna are reported with reasonable agreement between the measured and simulated results observed. [ABSTRACT FROM AUTHOR]

This brief presents a new kind of adjustable dielectric waveguide resonator (DWR), based on which integrated designs of filtering circuits are conducted. The DWR is composed of a dielectric part as the main resonating body and a printed circuit board (PCB) part as the cover. An unmetallized blind hole is carved at the upper surface of the dielectric part. A tuning screw is installed on the PCB and inserted into the unmetallized blind hole to adjust the resonant frequency the DWR. This adjusting method is flexible and reversible. By using the proposed adjustable DWR, a fourth-order bandpass filter (BPF) is designed, fabricated and measured. The measured results show that the BPF is with an in-band insertion loss of 0.8 dB and an in-band return loss better than 19 dB. A capacitive cross coupling structure is constructed on the PCB so that two transmission zeros are introduced close to the passband to improve the filtering selectivity. In addition, a Wilkinson power divider is realized on the PCB and integrated with the above BPF, forming a filtering power divider. The measured in-band insertion loss of the filtering power divider is 1.1 dB. The isolation is better than 24 dB and the maximum phase imbalance is 1° in the passband. [ABSTRACT FROM AUTHOR]

The performance of a low-profile dielectric resonator (DR) antenna (DRA) is hardly maintained across a wide frequency range due to the multiple higher-order modes. In this letter, a low-profile and broadband DRA is proposed with stable broadside radiation over a wide range of frequencies. A detailed analysis of the excited modes is conducted to identify proper modes for broadband operation. Different air regions are then introduced in the top layer of the proposed DRA. This allows the excitation of the higher-order DR modes with broadside radiation while suppressing the unwanted off-boresight modes. To validate the design, the DRA is developed to cover the frequency range of 3.25–6.1 GHz for potential 5G applications. The fabricated prototype is measured showing a broad bandwidth of ∼64.2%, a peak antenna gain of ∼9 dBi, and a low profile of only ∼0.07λ0. [ABSTRACT FROM AUTHOR]

This letter presents a high-gain 32 × 32-element full corporate-feed array antenna using a simplified assembly of only two split blocks. This is made possible by a new feeding configuration which eliminates the cavity-backed layer used in conventional designs. E-plane T-junctions, as well as the single-ridge waveguide output structure, are used in the full corporate-feed network to reduce its size. This helps to realize the one-to-one corresponding excitation between the output port of the feed network and the radiation slots. In addition, a transition structure from single-ridge waveguide to double-ridge waveguide is employed to improve the impedance matching bandwidth of the radiation part. For demonstration, a prototype is designed, fabricated, and measured. Experimental results show that the array antenna achieves an impedance bandwidth of 19% (71–86 GHz) with input reflection coefficient better than −13 dB, the antenna efficiency of over 76.4%, and peak gain of better than 38.4 dBi over the entire operating band. [ABSTRACT FROM AUTHOR]

In this letter, a compact ±45° polarized base station antenna array fabricated using laser direct structuring (LDS) technique is presented. The proposed antenna array operates in fifth-generation (5G) NR band 41 (2496–2690 MHz). The simple antenna elements of the array consist of a modified patch radiator fed by Y-shaped probes realized by injection molding, which are amenable to efficient mass production. An antenna unit (AU) is investigated to meet the specification requirements in practical base-station applications. A prototype of the AU was manufactured and measured, and the results showed that it is able to fulfill the design requirements within the operating band. These features also show that this LDS-based antenna array would be a promising solution for 5G base station applications. [ABSTRACT FROM AUTHOR]

In this letter, a circularly polarized antenna featured with a low profile, wideband, and high gain is investigated. The antenna, looking like a classical stacked microstrip patch antenna (MPA), is essentially a stacked dielectric resonator antenna (DRA) with high permittivity thin dielectric slabs introduced instead of metallic patches. With this structure, the antenna can take advantages of both MPA and DRA, showing superior performance than either of them. On this basis, a polarization-reconfigurable antenna version is further proposed with three polarization states of right-handed (RH), left-handed (LH) circular polarization (CP) and linear polarization. For demonstration, antenna prototypes were fabricated and measured. Reasonable agreement between the measured and simulation results is observed. [ABSTRACT FROM AUTHOR]

A dielectric patch (DP) resonator (DPR) with silver-coated slots is investigated for designing wideband low-profile antenna in this communication. The low-profile DPR can be treated as an anisotropic dielectric resonator (DR) for analysis. A new equation for calculating the effective dielectric constant of the DPR operating at the TM modes is proposed. Based on this, the anisotropic property is investigated to enhance the gain of DP antenna (DPA). It is found from the theoretical analysis that the resultant antenna is a good compromise between the traditional microstrip patch antenna (MPA) and dielectric resonator antenna (DRA) in terms of profile, gain, efficiency, and design freedom. By making full use of the multimode characteristic of the DPR, the silver-coated slots are introduced on the DP to shift high-order TM121 mode close to TM101 mode. As a result, the bandwidth of the antenna can be significantly expanded. For demonstration, the DPA element and $1\times4$ array prototype operating in the microwave band (5 GHz) are implemented and measured. [ABSTRACT FROM AUTHOR]

The printed circuit board assembly (PCBA) tends to become a bottleneck in an assembly line of electronic products. For improvement, many assembly firms have introduced chip shooter machines. This, however, in turn, raises the issue of how to best utilize these machines. To deal with the PCBA problems, swarm intelligence (SI)-based metaheuristics have been increasingly popular due to the use of guided search that can better drive solutions toward optimality. In this study, we have proposed a novel SI-based metaheuristics, termed improved shuffled frog-leaping algorithm (I-SFLA2), to deal with the feeder assignment problem (FAP), and component sequencing problem (CSP) simultaneously for a chip shooter machine. With novel features such as self-adaptive jump, push jump, direct-jump prevention, and self-adaptive variant, the I-SFLA2 can develop smart jumps for frogs to approach and search around elites quickly while avoiding being trapped in local optima. The I-SFLA2 includes the strategy of transitioning from exploration to exploitation by decreasing the number of memeplexes iteratively. Our small-sized experiments showed the I-SFLA2 had a high hit rate to the optimal solution whereas big-sized experiments showed the I-SFLA2 outperformed the basic SFLA (B-SFLA), B-SFLA(2), the improved SFLA (I-SFLA1), as well as the PSO2 proposed in previous studies. The computational times for the I-SFLA2 were found also reasonable for practical usage. Note to Practitioners—Chip shooter machines have been widely used in industry for printed circuit board assembly (PCBA). Approaches such as exact approach, simple heuristics, and metaheuristics have been proposed for PCBA planning. Although with the capability to find the optimal solution, the exact approaches are found to be computationally intractable when used to deal with a problem of a practical size. Although simple heuristics are easy to use, they usually have the difficulty to find the optimal/near-optimal solution. One recent trend is using metaheuristics to solve PCBA problems as they can avoid the computational intractability of exact approaches while improving over simple heuristics to find a better solution. In this study, we propose an improved shuffled frogs leaping algorithm (I-SFLA2), an advanced swarm intelligence (SI)-based metaheuristic to solve the CSP and FAP simultaneously for a chip shooter machine. With new features and smart jumps, the I-SFLA2 is able to find a better solution compared to some previously-proposed methods. [ABSTRACT FROM AUTHOR]