Improved Microstrip Antenna with HIS Elements and FSS Superstrate for 2.4 GHz Band Applications

Abstract

This research presents a microstrip antenna integrated with the high-impedance surface (HIS) elements and the modified frequency selective surface (FSS) superstrate for 2.4 GHz band applications. The electromagnetic band gap (EBG) structure was utilized in the fabrication of both the HIS and FSS structures. An FR-4 substrate with 120 mm × 120 mm × 0.8 mm in dimension (W × L × T) and a dielectric constant of 4.3 was used in the antenna design. In the antenna development, the HIS elemental structure was mounted onto the antenna substrate around the radiation patch to suppress the surface wave, and the modified FSS superstrate was suspended 20 mm above the radiating patch to improve the directivity. Simulations were carried out to determine the optimal dimensions of the components and the antenna prototype subsequently fabricated and tested. The simulation and measured results were agreeable. The experimental results revealed that the proposed integrated antenna (i.e., the microstrip antenna with the HIS and FSS structures) outperformed the conventional microstrip antenna with regard to reflection coefficient, the radiation pattern, gain, and radiation efficiency. Specifically, the proposed antenna could achieve the measured antenna gain of 10.14 dBi at 2.45 GHz and the reflection coefficient of less than −10 dB and was operable in the 2.39-2.51 GHz frequency range.

Broadband planar slot antenna using a simple single‐layer FSS stopband

“…Moreover, the radiation patterns for both structures are simulated and validated by measurements in an anechoic chamber for the E-plane (YZ) and H-plane (XZ) at several frequencies, including 4, 5.2 and 5.8 GHz, as plotted, respectively, in Figs. [14][15][16]. The obtained results indicate that the normalised radiation patterns, without FSS, are bidirectional in the E-plane and quasiomnidirectional in the H-plane.…”

“…The proposed antenna is compared with the most relevant of those reported in the literature, and the results are summarised in Table 3. As exposed in this table, the proposed structure exhibits a better characteristic in terms of size, profile, gain enhancement and bandwidth rather than those presented in [18,19,15]. However, in [16] the directivity improvement of 6.9 dBi is achieved at 10.8 GHz, but with a high profile and an insignificant bandwidth (5.5%).…”

“…Regarding the problem in how to redirect the back radiation and hence increasing the gain and directivity of microstrip antenna with wide impedance bandwidth, several techniques, based on the combination of FSS layer with other periodic structures such as metamaterial, FSS/EBG, FSS/AMC, or FSS/HIS, have been proposed in the literature. As examples, we can cite Jerusalem cross-shaped FSS (JC-FSS) used as an artificial magnetic conductor (AMC) ground plane [12], metamaterial reflective surface (MRS) used as a superstrate for a single-feed microstrip patch antenna [13], integrated metamaterial loading used in beam tilting antenna [14], high impedance surface (HIS) elements, with the modified FSS (MFSS), employed as superstrate of microstrip antenna [15] and FSS properties of a uni-planar EBG used as superstrate of microstrip antenna [16]. Several other complex structures, based on the use of only a simple FSS technique, have been also proposed in the literature to get a higher gain with a very wideband antenna.…”

Angularly stable frequency selective surface for the gain enhancement of isolated multiple input multiple output antenna

“…They also have the possibility of presenting surface wave propagation, reducing their efficiency 1 . In the References 3–9, studies have been carried out to improve the performance of microstrip antennas such as gain, directivity, and bandwidth (BW).…”

“…In recent years, to improve the performance of the antenna, additional periodic structures in the form of substrates or superstrates have been loaded above the antenna or below the antenna 6–24 . In the References 15,16, the metamaterial structure was designed and loaded to the antenna to improve its performance.…”