Development of multiband microstrip antennas for GPS applications

Önder, Mustafa Caner
In this thesis study, the design, fabrication and measurements of dualband and triband circularly polarized microstrip antennas for GPS applications are presented. Characteristic mode analysis technique is applied to get an insight into circularly polarized patch antennas. A design flow is presented for a circularly polarized L1 GPS band microstrip antenna by using characteristic mode analysis. A single fed L1/L2 GPS band right hand circularly polarized four-slotted patch antenna is designed by using reactive loading technique. A novel zigzag four-slotted patch is designed to operate at L1/L2 GPS bands without the need of reactive loading and designed antenna is fabricated. The frequency ratio of 1.31 is achieved with zigzag four-slotted patch. The axial ratios 7.5 dB and 8.1 dB are measured at lower and higher operating bands, respectively. An L1/L2/L5 GPS band single fed right hand circularly polarized two-layer stacked antenna is designed and fabricated. In measurements, it is seen that the impedance bandwidths of 58 MHz, 28 MHz and 11 MHz are achieved at operating frequencies. The axial ratios of 0.7 dB, 8 dB and 7.5 dB are measured at operating frequencies. An L1/L2/L5 GPS band single fed right hand circularly polarized three-layer stacked antenna is designed and fabricated. In measurements, the impedance bandwidths of 71.1 MHz, 4 MHz and 32 MHz are achieved at the center frequencies of L5, L2 and L1 GPS bands, respectively. The axial ratios of 0.7 dB and 3-dB axial ratio bandwidth of 5 MHz are measured at L1 GPS band. The lowest axial ratios of 1.5 dB and 8.9 dB are measured at the lowest and the middle operating frequencies, respectively.


Dual frequency bi-orthogonally polarized antenna for GPS applications
Alatan, Lale; Mahale, A; Balasubramanian, A; Olin, RP (2000-01-01)
Design, fabrication and testing of dual frequency bi-orthogonally polarized microstrip patch antenna structures for GPS receivers are studied. The considered configurations include orthogonally placed coplanar rectangular patches, orthogonally stacked rectangular patches and stacked square patches. Designed antennas are fabricated according to the optimized parameters, tuned in the presence of radomes and then measured for their bandwidth, input matching, radiation pattern, gain, and polarization characteri...
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...
Design and Analysis of Nanoantenna Arrays for Imaging and Sensing Applications at Optical Frequencies
Isiklar, Goktug; Cetin, Isa Can; Algun, Mustafa; Ergül, Özgür Salih (2019-01-01)
We present computational analysis of nanoantenna arrays for imaging and sensing applications at optical frequencies. Arrays of metallic nanoantennas are considered in an accurate simulation environment based on surface integral equations and the multilevel fast multipole algorithm developed for plasmonic structures. Near-zone responses of the designed arrays to nearby nanoparticles are investigated in detail to demonstrate the feasibility of detection. We show that both metallic and dielectric nanoparticles...
Design of a dual polarized low profile antenna for microwave brain imaging
Üçel, Kaan; Alatan, Lale; Department of Electrical and Electronics Engineering (2022-5-9)
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 uni...
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
M. C. Önder, “Development of multiband microstrip antennas for GPS applications,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Electrical and Electronics Engineering., Middle East Technical University, 2019.