Design of a dual polarized low profile antenna for microwave brain imaging

Üçel, Kaan
In this thesis, a low profile, low cost, wide band (0.9-2GHz) dual linearly polarized printed dipole antenna is designed to be used in microwave brain imaging systems. Dual polarization feature offers superior data acquisition through polarization diversity for better image quality. Starting from a simple printed dipole, antenna structure is modified step by step to meet these design requirements. Since a conductive surface in close vicinity of the antenna affects antenna performance, in order to obtain unidirectional radiation from the dipole, instead of an electric conductor, a frequency selective surface (FSS) surface is utilized to obtain a low profile antenna. The designed antenna has 11x11x1.8 cm dimensions. The antenna is manufactured on a FR-4 substrate by laser etching machine. Return loss performance and radiation pattern characteristics are measured in an anechoic chamber. Measurement and simulation results have been compared with each other and satisfactory relevance is achieved.


Design of series-fed printed slot antenna arrays excited by microstrip lines
İncebacak, Mustafa; Alatan, Lale; Department of Electrical and Electronics Engineering (2010)
Series-fed printed slot antenna arrays excited by microstrip lines are low profile, easy to manufacture, low cost structures that found use in applications that doesn’t require high power levels with having advantage of easy integration with microwave front-end circuitry. In this thesis, design and analysis of microstrip line fed slot antenna arrays are investigated. First an equivalent circuit model that ignores mutual coupling effects between slots is studied. A 6-element array is designed by using this e...
Design of a Re-configurable dual frequency microstrip antenna with integrated RF MEMS switches
Onat, Sinon; Ünlü, Mehmet; Alatan, Lale; Demir, Şimşek; Akın, Tayfun (2005-07-08)
The complete design of a re-configurable dual frequency antenna structure, including its integrated RF MEMS switches and their actuation lines together with a CPW feed, is introduced. The number of switches used in the inset is decreased compared to the hybrid design we presented previously (Onat, S. et al., IEEE Int. Antennas and Propag. Symp., vol.2, p.1812-15, 2004). Instead of utilizing available RF MEMS switches, new switches suitable for this application are designed. Two different switch configuratio...
Beam Steerable Traveling Wave Meander Line Antenna Using Varactor Diode for X-Band Applications
Gokalp, Nihan; Aydın Çivi, Hatice Özlem (2008-07-11)
This paper presents a novel beam steerable meander line antenna with varactor diode for X-band applications. Beam steering has been achieved by loading the arms of the meander line antenna with varactor diodes. The capacitances of the varactor diodes have been controlled by DC bias voltage. Instead of varactor diodes, RF-MEMS variable capacitances can be used to scan the beam. Since the insertion loss of MEMS capacitances are small compared to loss of varactor diodes, use of MEMS capacitors will increase th...
Reconfigurable antenna structure for RFID system applications using varactor-loading technique
Sevinç, Yusuf; Kaya, Adnan (2012-01-01)
A novel method is presented for electrically tuning the frequency of a compact radio-frequency identification (RFID) tag antenna. A tuning circuit, comprising a radio frequency (RF) switch and discrete passive components, was completely integrated into the antenna element, which is thus free of DC wires. The low-profile printed antennas were fabricated together with the layouts of the DC control circuits and other RF/baseband circuit footprints. A surface-mounted varactor was applied as a frequency-tuning e...
Design of Irregularly Shaped Patch Antennas by using the Multiport Network Model
Sener, Goker; Alatan, Lale; Kuzuoğlu, Mustafa (2008-07-11)
The multiport network model (MNM) is an analytical method that is used to analyze microstrip antennas. MNM is based on defining ports along the periphery of the patch and evaluating the impedance matrix corresponding to these ports by using the Greenpsilas function for the cavity under the patch. For regular rectangular, triangular and circular patches, analytical expressions for the Greenpsilas function are available. In the analysis of irregular patches, Greenpsilas functions cannot be calculated explicit...
Citation Formats
K. Üçel, “Design of a dual polarized low profile antenna for microwave brain imaging,” M.S. - Master of Science, Middle East Technical University, 2022.