Rectangular DR-based dual-band CP-MIMO antenna with inverted Z-shaped slot

ABSTRACT

In this paper, a dual-band circular polarised (CP), Multiple Input Multiple Output (MIMO) antenna with bi-directional polarisation is presented. Designed antenna is operating at two frequency bands i.e. 5.4 GHz–6.2 GHz and 7.0 GHz–7.4 GHz. A rectangular dielectric resonator (DR) is excited by two ports for designing an MIMO antenna system. To generate the Circular polarisation, ground plane is modified by etching an inverted Z-shaped slot. The fundamental mode ${\mathrm{T}\mathrm{E}}_{111}^{\mathrm{X}}$, ${\mathrm{T}\mathrm{E}}_{111}^{\mathrm{Y}}$ and higher order mode ${\mathrm{T}\mathrm{E}}_{121}^{\mathrm{X}}$, ${\mathrm{T}\mathrm{E}}_{121}^{\mathrm{Y}}$ are generated in the antenna structure due to the specified geometry which excites the circular polarisation. 3-dB axial ratio (AR) bandwidth of 300 MHz (5.7 GHz–6.0 GHz) and 200 MHz (7.0 GHz–7.2 GHz) is obtained for the lower and upper bands, respectively. Maximum isolation is 19 dB, and 15 dB for the targeted bands have been achieved. S-parameters, gain and radiation pattern are measured to authenticate the simulated results. Envelope correlation, diversity gain, mean effective gain and channel capacity loss are calculated from the measured parameters; their values lie within the optimum range. Results show that antenna is suitable for WLAN 5.5/5.8 GHz and X-band downlink communication at 7.0 GHz.

KEYWORDS:

• Circular polarisation
• multiple input multiple output
• bi-directional polarisation
• z-shaped slot

Disclosure statement

No potential conflict of interest was reported by the author.