Low profile broadband circularly polarized magnetoelectric dipole antenna with short‐circuit patch for wireless communication

Abstract

A short‐circuit load broadband circularly polarized (CP) magnetoelectric (ME) dipole antenna is proposed for WiMAX, Global System for Mobile Communications (GSM), and Radio Frequency Identification (RFID). The co‐directional electric dipole and magnetic dipole work together to radiate CP electromagnetic waves. The magnetic dipole is realized by a pair of vertical grounded metal patches and the electric dipole is accomplished by a pair of rotationally symmetric horizontal metal patches. The outer edges of the horizontal patches are extended to bend downward and shorted to ground for low‐profile, miniaturization, and axial ratio (AR) bandwidth enhancement. A pair of knife‐shaped horizontal patches effectively enhances the AR bandwidth of the proposed antenna. A prototype is fabricated, and the measured results show that the proposed antenna achieves 67.2% (1.7‐3.42 GHz) 3‐dB AR bandwidth and 87.5% (1.33‐3.4 GHz) impedance bandwidth for |S11| ≤ 10 with a small size of 0.8λL × 0.386λL × 0.177λL (λL denotes to the maximum operation frequency). Over the entire AR frequency band, stable radiation pattern is obtained. Furthermore, the maximum boresight gain is up to 10.4 dBic at 2.4GHz, and the boresight gain is greater than 4.2 dBic over 3‐dB AR band.

Low-Profile and Wideband Circularly Polarized Magneto-Electric Dipole Antenna Excited by a Cross Slot

“…Compared to previous CP ME dipole antennas ( [17], [20], and [21]), the proposed antenna exhibits a wider CP bandwidth and a higher gain while maintaining a very low profile of only 0.134λ L . Although three earlier antennas ( [18], [19], and [22]) have a wider CP bandwidth and a slightly higher gain their profiles are quite high. Compared to one design [23], the proposed antenna provides a much wider 3 dB AR bandwidth and a much higher gain.…”

“…By adding strips that were bent downward to the ends of horizontal trapezoidal patches and introducing a cavity reflector with four gaps, a CP ME dipole antenna with a low profile of 0.16λ L was developed [18], reportedly achieving a wide 3 dB AR bandwidth of 79.7% (1.6-3.72 GHz). A CP ME dipole antenna with a wide 3 dB AR bandwidth of 67.2% and a low profile of 0.177λ L was VOLUME 4, 2016 presented by adding vertically shorted plates to the outside edges of the horizontal planar electric dipole [19]. These CP ME antennas in all cases were excited by a suspended Γshaped probe.…”