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This paper presents a novel metamaterial based on Jerusalem cross structure with interdigital technique to be applied for dual-band systems. The proposed structure can operate at resonant frequencies of 1.8 and 5.5 GHz for LTE and WLAN bands, respectively. The interdigital structure was added to connect at the end of the Jerusalem cross structure in order to control the resonant frequencies and to promote for permittivity adjustment. The proposed metamaterial unit cell was designed to achieve the simulated dual-band operation with bandwidths of 1.70 ∼ 1.95 GHz at 1.8 GHz and 5.06 ∼ 6.04 GHz at 5.5 GHz, respectively. The unit cell size is reduced from λ/2 to λ/4 which is much smaller than the conventional structure. The 5×5 unit cells of metamaterials were implemented as a reflector for a dipole antenna resulting in dual-band operation with bandwidths of 1.58 ∼ 1.88 GHz at 1.8 band and 5.05 ∼ 5.68 GHz at 5.5 band, respectively. Besides, the dipole antenna with the proposed metamaterial reflector has measured gains up to 8.23 dBi at 1.8 GHz and 8.30 dBi at 5.5 GHz, respectively. Moreover, the shape of metamaterial structure is symmetrical, so it can be used for dual linear polarization. Also, the antenna with the proposed reflector has low profile with the distance of λ/8 between radiator and reflector. Therefore, the proposed metamaterial can be applied for any antenna applicable for LTE and WLAN applications.

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The conventional rectangular horns have been used for microwave antennas a long time. Its gain can be increased by enlarging the construction of horn to flare exponentially. This paper presents the new technique for improving its gain for conventional horn without construction enlargement. The quadratic-shaped of woodpile Electromagnetic Band Gap (EBG) and the mushroom-like EBG have been utilized to improve the gain instead. The important technique for gain improvement of this method that is, the electromagnetic fields from horn antenna will be transferred through its normal structure, then, 1×22 unit cells of mushroom-like EBG located on two side-wing slabs will help gain the energy of EM fields and suppress some surface waves that occurred on each side-wing slabs. The yielding waves will be transferred forward to the woodpile EBG for increasing gain in the last step. The proposed technique has the advantages of low profile, low cost for fabrication and light weight. The antenna characteristics such as reflection coefficient (S 11 ), radiation patterns and gain of antenna are simulated by using A Computer Simulation Technology (CST) software. The gain at dominant frequency of 10 GHz is 27 dB that higher than the gain of the basic rectangular horn antenna around 9 dB with adding only one appropriated EBG structure.