Interest of Micro-Electromechanical System (MEMS) Keywords: micro-electromechanical systems (MEMS), THz bands, helix antennas, 3D-HFSS, electromagnetic optimization.Copyright © 2018 Universitas Ahmad Dahlan. All rights reserved. IntroductionAs new applications for the electromagnetic THz field begin to emerge, a new generation of efficient MEMS antennas [1] is developed to meet the specific requirements of these high frequency systems. Many new processes of MEMS technology are just beginning to stimulate interest in this unique spectral and continue to help manufacturing THz antennas, improving their performance and achieving micro-level precision [2]. Focused Ion Beam (FIB) is one of the important processes used for fabricating MEMS antennas, especially helical antennas [3] by implementing silicon wafers that represent a very good solution to enhance the antenna's radiation and performance. MEMS helix antennas employing silicon substrates, have achieved over the past few years interesting characteristics including compact size, high directional gain, and wide bandwidth, thus their implementation into planar forms seems to become easier due to the advanced micromachining techniques [4]. This has provided a new class of THz antennas with numerous wireless access applications thanks to the use of complex simulation tools to bring the CAD for such high frequency structures to its current state of the art. Accordingly, HFSS-based Q-N and SNLP approaches lead to excellent optimization solutions carrying out by replacing repeated electromagnetic simulations whilst still retaining a good accuracy as compared with finite element modeling to improve the accuracy of the existing design models or develop new design models. This procedure requires acceptable simulation time especially for defining the problem that needs reliable and fully functional approximations. This paper proposes for the THz frequency access systems a compact geometrical configuration of a wide MEMS Helix antenna using HFSS software. The MEMS antenna geometry is optimized using both Quasi-Newton and Sequential Non Linear Programming algorithms to offer fitness functions for excellent bandwidth learning and fast configuration evaluating. The antenna occupies a very compact volume of 79×80×152 um (0.960 10-3 mm3) including the silicon substrate having a thickness of 9.3 um and a dielectric constant of 11.9.

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Sub strate Integrated Waveguide (SIW) antennas are considered as main radiators for RF and microwave wireless systems due to their low profile, low cost and soft integration with the other devices. The gain of a SIW patch antenna may b e enhanced using different techn iques such as Artificial Neural Networks (ANN) b y modifying the antenna's geometry with high efficiency comparing to electromagnetic techniques that take more time. This paper describ es a novel structure of a circular SIW patch antenna design using a tree-dimensional electromagnetic (3D-EM) simulation b ased on ANN model which is developed as an accurate tool for synthesizing the forward side and then analyzing the reverse side of the prob lem. In this work, ANN algorithms are used for training the samples to provide precise geometrical dimensions of the SIW patch antenna with high accuracy for the target requirements. The antenna is designed to operate in Ku and K frequency b ands, resonate at 16.10 GHz and 19.81 GHz respectively and show good performance resulting in low return losses of less than-10dB to-29dB for the selective frequency b ands.

Sub strate Integrated Waveguide (SIW)

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