Dual‐band metasurface‐based CP low‐profile patch antenna with parasitic elements

Abstract

A single‐feed dual‐band circularly polarised (CP) patch antenna is proposed. The antenna consists of a corner‐truncated square patch antenna and a superstrate composed of a lattice of 2 × 2 metallic patches surrounded by parasitic elements. The driven patch generates one resonant mode. The metasurface with parasitic elements excites two additional resonant modes (TM10 and TM20). The combined resonances result in minimum axial ratio points, and a good dual‐band CP operation is achieved. Simulations show that the antenna has a CP operating bandwidth of 40 MHz centred at 3.72 GHz (1.07%), and a CP operating bandwidth from 5.37 to 6.05 GHz (11.9%). The simulated gain is ∼7.05–7.1 dBic for the low‐frequency band and 4.17–6.07 dBic for the high‐frequency band, respectively. Measurements and simulations are in good agreement.

Metasurface-Based Single-Layer Wideband Circularly Polarized MIMO Antenna for 5G Millimeter-Wave Systems

“…The sub-wavelength two-dimensional periodic structures known as MS have been widely used for antenna's performance enhancement by exploiting surface wave resonances [26][27][28][29]. These designs consist of two separately printed layers, the MS layer and the patch radiator layer.…”

“…The MS layer was directly stacked above the radiator to reduce the antenna height. The proposed single-layer CP antenna is based on these studies [26][27][28][29], where the antenna performance is improved by employing a MS of periodic square metallic plates to excite surface waves propagating along the MS for extra resonances. The propsed MS also achieve extra resoannces both in |S11| and AR profiles as shown previously in Figure 3.…”

“…For the phase shift of 90°, the intersection between dispersion lines and the vertical line shows the solution of equation 5, which represents the resonance point of the MS. For the proposed configuration, the surface waves are predicted to resonate around 28 GHz. Here, only the first two eigenmodes (TE and TM) are shown because these dominant modes have good broadside radiation based on the work done in [26][27][28][29]. It is noted that these studies used 4 × 4 unit cell MS, while we used 6 × 6 unit cells to compensate the removed unit cells to print radiator and the MS in the same layer.…”

“…Again, the gap between the radiator and the MS layer poses the aforementioned problems. Furthermore, radiators are sandwiched between the MS layer and ground plane without the air gap to improve performance keeping the planar structure of the antennas [23][24][25][26][27][28][29][30]. Even so, these configurations have the critical drawback of multiple-layers of the printed substrate (MS layer and radiator layer), which increases fabrication cost and complex design architecture.…”

Broadband Metasurface Antenna Using Hexagonal Loop-Shaped Unit Cells

“…Although merits in microstrip antennas such as low-profile and low-cost can be obtained, they still suffer from narrow operating bandwidths [1]- [5]. Various techniques have been investigated to improve the antenna bandwidth, employing aperture coupling, stacked patches, parasitic resonators, modified feeds, and reactive slotloading [5]- [10], etc. Recently, a new perspective called metasurface (MTS) based antennas is proposed to improve the antenna bandwidth by means of manipulating electromagnetic waves [1]- [2].…”