Topology Optimization Method Of Monopole Antennas Based On MoM Analysis

Nowadays communication needs lead to a rapid development of wireless communication technology. The antenna as an important part of ratio equipment, has become a key factor influencing the performance of communication equipment. Thus, antennas structure optimization considered to be complex becomes an advanced research hotspot. Classical method of antennas design is based on experience, prior antenna configurations or parameter optimization. The lack of innovative design and theoretical basis calls the need of a systematic way. Topology optimization is a high-level systematic method used during the design process to achieve conceptual design. It directly explores for structural internal layout and connection form, producing creative conceptual configuration. It is considered to be the most significant process during structure design. Conducting antenna design by using topology optimization method is an inevitable trend. Besides, the progress of computational electromagnetics method provides numerical foundation for topology optimization. Based on the above discussion, this paper focuses on the antenna optimization design using topology optimization method. Choosing the Method of Moments as numerical analysis technique, the topology optimization design of monopole antenna is realized.a) This paper uses MoM as the numerical analysis method of monopole antenna. There is a simple description of the MoM basic theory and its application in antenna numerical simulation. By discussing the MoM combined with Rao-Wilton-Glisson basis functions in detail, the solution of antenna surface current density is obtained as well equations of performance parameters. There is also an illustration of the process flow chart. Numerical examples testified the applicability of the MoM in antenna analysis. As a reference for comparison, results of finite elements codes Ansoft HFSS is included, concluded that MoM has an advantage in analysis efficiency.b) A topology optimization model of monopole antenna is established. Considering maximum the radiation efficiency of antenna, a metal material layout approach is introduced to conduct the antenna optimization design. With the SIMP topology technique, the design domain of monopole antenna is divided into a series of elements and described by artificial elements densities which are exactly the design parameters. The material interpolation function is proposed in a Tangent form and its physical meaning is given. On the basis of monopole antenna energy balance, the objective function to maximum radiation efficiency and its sensitivity are both derived. Numerical examples verified the validity of the topology optimization model. To eliminate gray scale in the topology results, a threshold way is used and modified dynamic penalty is proposed. Numerical examples show that distinct topology can be acquired using the proposed penalty method.c) A configuration design of multi-band monopole antenna. Aiming at commercial communication demands, the antenna which cover a variety of working frequency bands is in great need. Utilizing the proposed optimization method, an innovative configuration of planar monopole antenna that covers the working band of GPS, DCS, PCs and TD-SCDMA is achieved. Optimization example shows that the proposed topology optimization model of monopole antenna could lead to an creative design at specified frequency bands.