A compact planar quad-element ultrawideband (UWB) antenna with a band-notch and low coupling for multiple-input multiple-output (MIMO) system is proposed in this paper. The antenna consists of four circular monopoles with modified defected ground plane and a periodic electromagnetic band gap (EBG) structures. The proposed EBG structures are modified from the traditional mushroom-like ones, comprised of patterns of grids on the top patch, the metallic ground plane, and several vias that connect the top and bottom plane. It is printed at the center of the dielectric substrate to lower electromagnetic coupling between the parallel elements. Besides, by etching four crescent ring-shaped resonant slots on the radiators, a sharp band-notched characteristic is achieved. From the experimental results, the −10 dB bandwidth of the antenna is extended covers from 3.0 to 16.2 GHz, with a sharp notched band at 4.6 GHz. And the isolation is greater than 17.5 dB between its elements, with a peak gain of 8.4 dB and a peak efficiency of 91.2%. Moreover, it has a compact size of 0.6λ×0.6λ×0.016λ at 3 GHz and could be a good candidate for portable devices.

No abstract

that of the nonself-aligned RTD. The calculated f C of the self-aligned RTD is increased by about 13.6% compared with that of the nonself-aligned RTD. The results show that the fabricated self-aligned RTD with the SiN X sidewall process improves the RF performance by reducing the spacing (d) resulting in lower R S due to reduced R SEMI . By using a scaled-down device technology with an electron beam lithography, the high-speed characteristics of the self-aligned RTDs will be improved. | C ONCL US I ONA self-aligned RTD using a SiN x sidewall process has been fabricated and characterized. The dry etching process has been developed for the self-aligned RTD with 5 lm 2 emitter size to obtain the highly anisotropic mesa profile. The fabricated RTD showed the PVCR of 13.1 with a peak voltage (V P ) of 0.348 V. The measured peak currents and peak voltages were almost constant in the temperature range between 25 and 1258C. The self-aligned RTD showed the R S reduction of 27% compared with the nonself-aligned RTD by reducing the spacing between emitter mesa and collector metal. The results achieved in this work indicate that the self-aligned RTD with the SiN X sidewall will offer a viable option for the future high-speed microwave applications. ORCIDKiwon Lee http://orcid.org/ AbstractIn this work, a novel very wideband 4-element monopole based multiple-input multiple-output (MIMO) antenna system with single connected antenna array (CAA) is presented. The CAA is based on a single slot which is etched on the ground plane. A 2 3 1 power divider/ combiner is used to excite the slot to act as a CAA. The

No abstract

ChiCTR-ONC-13003291.