Dual-band Microstrip Antenna Array Research Articles

Isolation Enhancement in Dual-Band Microstrip Antenna Array Using Asymmetric Loop Resonator

This letter presents the design of a wideband decoupling element for mutual coupling reduction in microstrip antenna arrays. The proposed decoupling unit cell consists of an asymmetric loop resonator with a coupled microstrip line for wide stopband characteristics from 2 to 5 GHz. The bandgap characteristic of the decoupling element is analyzed, and the results are presented. Furthermore, the resonator is deployed in a two-element dual-band microstrip antenna array, and mutual coupling reduction is demonstrated. The decoupling unit cell has a lateral dimension of 2.84 mm and hence enables the packing of antenna elements in very close proximity with reduced mutual coupling. The proposed solution offers additional isolation greater than 15 dB in a V-slot loaded dual-band antenna with edge-to-edge element spacing of ${\text{0.057}}\,\lambda _{o}$ . The prototype dual-band antenna array with decoupling element is fabricated, and the simulation results are validated using experimental measurements.

Electromagnetic coupling reduction in dual-band microstrip antenna array using ultra-compact single-negative electric metamaterials for MIMO application**Project supported by the National Natural Science Foundation of China (Grant No. 61372034).

In this paper, an ultra-compact single negative (SNG) electric waveguided metamaterial (WG-MTM) is first investigated and used to reduce the mutual coupling in E & H planes of a dual-band microstrip antenna array. The proposed SNG electric WG-MTM unit cell is designed by etching two different symmetrical spiral lines on the ground, and has two stopbands operating at 1.86 GHz and 2.40 GHz. The circuit size is very compact, which is only (where λ0 is the wavelength at 1.86 GHz in free space). Taking advantage of the dual-stopband property of the proposed SNG electric WG-MTM, a dual-band microstrip antenna array operating at 1.86 GHz and 2.40 GHz with very low mutual coupling is designed by embedding a cross shaped array of the proposed SNG electric WG-MTM. The measured and simulated results of the designed dual-band antenna array are in good agreement with each other, indicating that the mutual coupling of the fabricated dual-band antenna array realizes 9.8/11.1 dB reductions in the H plane, 8.5/7.9 dB reductions in the E plane at 1.86 GHz and 2.40 GHz, respectively. Besides, the distance of the antenna elements in the array is only 0.35λ0 (where λ0 is the wavelength at 1.86 GHz in free space). The proposed strategy is used for the first time to reduce the mutual coupling in E & H planes of the dual-band microstrip antenna array by using ultra-compact SNG electric WG-MTM.

Microstrip-fed Circularly Polarized Antenna Array Using Semi-fractal Cells for Implicational Band

ABSTRACTIn this paper, extracted results are presented for a novel dual-band microstrip antenna array with circularly polarized property for second band whose design process is categorized in two main steps: (1) semi-fractal element design, (2) dual-transformed feed network design. The circularly polarized semi-fractal radiator patch is fed through a symmetric microstrip, dual-transformed, and incorporating bended methods in the corners of feed strips in order to reduce its radiation distortion effect and cross polarization level. The semi-fractal element of the array exhibits an impedance bandwidth from 3.8 to 7.2 GHz, and 3 dB axial-ratio from 5.2 to 5.6 GHz. A 1 × 4 novel semi-fractal element of antenna array was linked together using dual-transformed feed network to improve its radiation performance. The measured 3 dB axial-ratio (AR) of the antenna array extends from 4.85 to 5.82 GHz, and impedance bandwidth is between 3.4 and 4 GHz in band I and between 5.1 and 6.7 GHz in band II for voltage standing wave ratio (VSWR) ≤ 2.

Dual band space‐FED microstrip antenna arrays with orthogonal polarization

AbstractA high gain dual band microstrip antenna array with orthogonal polarization is proposed using space‐fed configuration. The feed network in the array is eliminated which improves the efficiency. Simulated and measured results are presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:793–795, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25851

Dual-band switched beam array fed by dual-band Butler matrix

A two layer dual-band switched beam system operating at two separate frequency bands is proposed. This system consists of a dual-band 4×4 Butler matrix at the bottom layer and a dual-band microstrip antenna array at the top layer. The antenna array is fed by a Butler matrix to produce four beams that can be tilted in different four directions. A modified Butler matrix consists of branch line couplers and −45° phase shifters without any crossovers. The system provides a tilted beam of ±14° and ±47° at 3.95 GHz and ±10° and ±28° at 7.3 GHz.

Dual-band microstrip antenna array with a combination of mushroom, modified Minkowski and Sierpinski electromagnetic band gap structures

A novel concept involving a single-port dual-band microstrip antenna array (DbMSAA) incorporated with electromagnetic band gap (EBG) structures is reported. Three types of EBG structures are used in the designs, which include the mushroom EBG, a modified Minkowski EBG and Sierpinski EBG structures. These EBG structures operate like a band rejecter, separating the branch of feed lines feeding two different groups of arrays of patch antennas, thus making them operate individually at their particular frequencies, simultaneously. Initially, with the new DbMSAA model configuration, the possibilities of having uniform and controlled radiation patterns are quite complicated to achieve because of the single-port feeding technique used and developments of grating lobes at the higher band frequency. By incorporating the EBG structures, these problems are solved. The antenna's performance improves with the radiation patterns of the dual-band antenna at both frequencies becoming more symmetrical and having increased gain.