Broadband loaded dipole antenna design by genetic algorithm optimization

Download
2014
Asan, Bahri
It is well known that standard dipole antenna is not convenient to be used in broadband wireless communication applications because of its narrow frequency bandwidth. To broaden the bandwidth of a dipole, lumped loading is the generally applied method. Positive effects of resistive, capacitive and inductive loading are discussed and proved for a pretty long time. This thesis investigates broadband lumped loaded dipole antenna design procedure by using genetic algorithm optimization techniques. First, unloaded dipole antenna numerical analysis formulation is provided by EFIE (Electric Field Integral Equation) derivation. MoM (Method of Moments) is used for numerical solution. Then, analysis is extended for lumped loaded dipole antenna. Analysis computer code is developed in MATLAB environment and results are compared with NEC (Numerical Electromagnetic Code). To design loaded dipole antenna with corresponding matching network which satisfies the predefined radiation parameters, genetic algorithm (GA) optimization methods are used . GA searches for an optimal solution from random solution set with iterative methods. Optimization objectives are selected as increasing the minimum antenna gain and decreasing the maximum VSWR. Load values, positions and matching network variables are optimized simultaneously. Finally, successfully optimized broadband loaded dipole antenna and matching network design examples are presented to verify the used procedure.

Suggestions

Analysis and design of dual-polarized wideband patch antennas electromagnetically excited with elevated wide strips /
Yılmaz, Adil Fırat; Alatan, Lale; Department of Electrical and Electronics Engineering (2015)
In communication systems like WiMAX, WLAN, 3G, 4G and LTE, design of wideband and dual polarized antennas are required. It is known that bandwidth of patch antennas can be broaden by using thick air substrates. The bandwidth can be further improved by using three dimensional feed strucutures that are electromagnetically coupled to the patch. In this thesis, microstrip patch antennas that are excited by elevated wide strips are studied. First, a linearly polarized antenna is considered and the effects of ant...
X Band TX reject waveguide bandpass filter design for satellite communication systems
Çelebi, İrem; Koç, Seyit Sencer; Department of Electrical and Electronics Engineering (2018)
For several applications such as satellite communication, filters are required since antenna systems are operating as both receiving and transmitting. There is a possibility of leakage from transmit to the receive path in these kind of systems which needs to be isolated in order to protect equipments after filter. Low loss, high isolation and bandpass characteristics are desired for the filtering, which can be validated with waveguide filters. In this study, bandpass waveguide filter design operating in X-Band f...
Polarization diversity in channel modeling for mimo systems
Söker, Burak; Tuncer, Temel Engin; Department of Electrical and Electronics Engineering (2013)
In a multiple-input multiple-output (MIMO) system, inter-antenna distances can be made large and uncorrelated signals can be transmitted and received when there is sufficient space at the transmitter (TX) and receiver (RX). When the antennas are closely spaced, diversity advantage is lost and communication performance degrades. In this case, polarization diversity can be used in order to decrease the correlation and improve communication performance. A detailed channel model, which includes both cross polar d...
Design of magneto-electric dipole antenna for wideband communication systems
Alparslan, Semih; Alatan, Lale; Department of Electrical and Electronics Engineering (2018)
This thesis includes the design, simulation, production and measurement of a differential fed magneto-electric dipole antenna with cavity operating at ultrawideband (3.3 GHz – 10 GHz). This antenna consists of a differential feeding structure, an electric dipole, a magnetic dipole and a cavity. The ultra-wideband operation is achieved through the use of differential feeding structure and cavity. A step-by-step procedure is followed during the design process of the differential fed magneto-electric dipole an...
Blind channel estimation based on the Lloyd-Max algorithm innarrowband fading channels and jamming
Dizdar, Onur; Yılmaz, Ali Özgür; Department of Electrical and Electronics Engineering (2011)
In wireless communications, knowledge of the channel coefficients is required for coherent demodulation. In this thesis, a blind channel estimation method based on the Lloyd-Max algorithm is proposed for single-tap fading channels. The algorithm estimates the constellation points for the received signal using an iterative least squares approach. The algorithm is investigated for fast-frequency hopping systems with small block lengths and operating under partial-band and partial-time jamming for both detecti...
Citation Formats
B. Asan, “Broadband loaded dipole antenna design by genetic algorithm optimization,” M.S. - Master of Science, Middle East Technical University, 2014.