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A novel planar lens structure is proposed by using metasurfaces to convert cylindrical‐like surface wave to inclined nondiffracting wave with a deflection angle. Based on the geometric optics, the refractive index distribution of the surface wave lens is derived. A square metal ring‐shaped metasurface cell is used for realizing small refractive index whilst two opposite E‐shaped metal patches are used to form the meta‐cell with large refractive index. By adjusting the size of meta‐cells, the desired refractive index distribution is obtained after optimization. Measured results show that the inclined nondiffractive surface wave can be achieved with the maximum propagation distance of 99.72 mm at the tilted angle of 26.8°, which are consistent with the full‐wave simulation and numerical calculation results. The proposed meta‐lens achieves compact size, large titled angle, and long nondiffraction propagation distance, therefore could be well utilized in surface wave communication and nondestructive detection of surface defects. [ABSTRACT FROM AUTHOR]

In this letter, an efficient broadband microwave rectifier with compact size for wireless power transfer is presented. It is proven that the proposed voltage doubler is easier to be matched than the series diode rectifier to achieve a wide bandwidth. In our analysis, the voltage doubler itself is already matched without the input matching network at the lower frequency band. For higher frequency band matching, a short section of microstrip line is connected to the input port of the voltage doubler. Thus, the proposed rectifier can operate over a broad bandwidth. To verify the design concept, a rectifier is fabricated, and the measurement results demonstrate that the power conversion efficiency is greater than 50% from 0.1 to 4.3 GHz at an 18 dBm input power level, and is higher than 70% within a wide bandwidth of 76.9%. In addition, when the input power is 18 dBm, the peak efficiency is 76.36% at 1.4 GHz. The results show that the proposed rectifier has the merits of compact size, broad bandwidth, and high efficiency. [ABSTRACT FROM AUTHOR]

In this article, a novel lens antenna with wide beamwidth using three‐dimensional printing is proposed. The proposed antenna is comprised of a concave lens by using three‐dimensional printing, a lantern shaped patch with a parasitic ring, and eight loaded monopoles around the center. The antenna operating frequency is 5.8 GHz, and the prototype is implemented. The measured half power beamwidth are 142° and 130° at the xoz and the yoz planes, respectively. Besides, the antenna is low cost, easy to fabricated, and very low cross polarization. Measured results agree well with the simulation results. [ABSTRACT FROM AUTHOR]

This letter presents a reconfigurable leaky‐wave antenna for near‐field beam manipulation. The proposed antenna is based on a radial waveguide and a reconfigurable capacitive sheet, which is divided into four regions. To realize the reconfigurability, PIN diodes are electrically soldered to the gap between the adjacent patches in the upper surface except for the isolation zone, where no diodes are printed. By switching the states of PIN diodes in each region by turns, wavenumbers with two different azimuths are generated, thus the near‐field beam deflection can be achieved in different regions. By using the Genetic Algorithm, the PIN diodes are optimally deployed for realizing high antenna efficiency. The simulated (measured) results show that with the implementation of the reconfigurable capacitive sheet results in a near‐field beam scanning property. The beam deflection at a tilted angle of 17.4° (16.2°) can be achieved in different regions. [ABSTRACT FROM AUTHOR]

This letter presents a new design method for a tunable bandpass filter with independently and widely tunable transmission zeros (TZs). Varactor‐loaded microstrip resonators are introduced to a fixed bandpass filter to realize the continuously tunable TZs. Although the tunable resonators have unloaded Q lower than 100, the insertion loss of the filter is not increased. The coupling matrix with the lossy resonators is synthesized and used to analyze the characteristic of the TZ‐tunable filter. A bandpass filter centered at 2 GHz with a 3‐dB bandwidth of 230 MHz is designed to validate the design concept. The measured results show good agreement with the simulated results. The fabricated filter has 2 TZs ranging from 1.4 to 1.8 GHz and from 2.28 to 3.08 GHz, respectively. The TZ‐tunable filter exhibits insertion losses ranging from 1.62 dB to 1.93 dB at the center frequency. The center frequency and bandwidth keep nearly unchanged when the TZs are tuned. [ABSTRACT FROM AUTHOR]

This article proposes a novel concept for constructing a microwave (MW) rectifying circuit by using a multilayer structure, aiming at reducing physical dimensions. Specifically, an embedded via-hole with connection of conductor layers in the multilayer structure is designed. A full-wave electromagnetic analysis is carried out to study the impacts of various via-hole design parameters. Then, a C-band rectifying circuit based on HSMS-286C Schottky diode is fabricated with the proposed multilayer structure for demonstration. The maximum MW-DC conversion efficiency of 61% has been measured. In comparison with the counterpart, namely a conventional microstrip rectifying circuit, the proposed multilayer circuit shows a great reduction of physical dimensions and a very similar efficiency, which validates that the proposed circuit can reduce physical dimensions significantly without sacrificing the MW-DC conversion efficiency. [ABSTRACT FROM AUTHOR]

ABSTRACT The transparent antenna can potentially be combined with solar cells to create multifunctional compact systems. In this article, an optically transparent broadside antenna is presented. Based on a meshed patch antenna which has three horizontal lines and three vertical lines, the antenna has four more lines to increase the bandwidth. The antenna is fed by a top fed for simple structure, and the area of the feed line is much smaller than the one of a side fed. The transparency is much better because of the low ratio of metal area, which can be further reduced without destroying the performance of the antenna. The transparent broadside antenna is studied at 2.5 GHz. On the upper surface of the antenna, the ratio of metal area is 3.2%, and the measured −10 dB impedance bandwidth is close to 60 MHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:146-149, 2015 [ABSTRACT FROM AUTHOR]

In this article, a novel microstrip grid array antenna is presented. For achieving a high gain and good impedance match, its structural parameters were optimized by a parallel genetic algorithm. A prototype antenna measures a gain of 18.3 dBi with an input return loss of -15.0 dB at its working frequency of 2.45 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2976–2978, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23856 [ABSTRACT FROM AUTHOR]