Microstrip antennas having posts for circular polarization

1984 ◽  
Vol 67 (9) ◽  
pp. 75-85 ◽  
Author(s):  
Shinobu Tokumaru ◽  
Satoru Fukui
Keyword(s):  
Circular Polarization ◽  
Microstrip Antennas

ANALYSIS PERFORMANCE OF SINGLY-FED CIRCULARLY POLARIZED MICROSTRIP ANTENNA FOR WIRELESS COMMUNICATION

2016 ◽  
Vol 78 (5-9) ◽  
Author(s):  
Muhammad Fauzan Edy Purnomo ◽  
Hadi Suyono ◽  
Panca Mudjirahardjo ◽  
Rini Nur Hasanah
Keyword(s):  
Wireless Communication ◽  
Circular Polarization ◽  
Microstrip Antenna ◽  
Axial Ratio ◽  
Microstrip Antennas ◽  
Impedance Bandwidth ◽  
Antenna Structure ◽  
Circularly Polarized ◽  
Large Bandwidth ◽  
Doubly Fed

The circularly polarized (CP) microstrip antennas, both of singly- and doubly-fed types, possess inherent limitation in gain, impedance and axial-ratio bandwidths. These limitations are caused mainly by the natural resonance of the patch antenna which has a high unloaded Q-factor and the frequency-dependent excitation of two degenerative modes (TM01 and TM10) when using a single feed. Many applications which require circular polarization, large bandwidth, and good performance, especially in the field of wireless communication, are still difficult to be designed by using antenna software. Some consideration to take will include the application target and design specification, the materials to be used, and the method to choose (formula, numerical analysis, etc). This paper explains and analyzes the singly-fed microstrip antenna with circular polarization and large bandwidth. This singly-fed type of microstrip antenna provides certain advantage of requiring no external circular polarizer, e.g. the 900 hybrid, as it only needs to apply some perturbation or modification to a patch radiator with a standard geometry. The design of CP and large-bandwidth microstrip antenna is done gradually, by firstly truncating one tip, then truncating the whole three tips, and finally modifying it into a pentagonal patch structure and adding an air-gap to obtain larger bandwidths of impedance, gain and axial ratio. The last one antenna structure results in a novelty because it is a rare design of antenna which includes all types of bandwidth (impedance, gain, and axial ratio) being simultaneously larger than the origin antenna. The resulted characteristic performance of the 1-tip (one-tip) antenna shows respectively 1.9% of impedance bandwidth, 3.1% of gain bandwidth, and 0.45% of axial-ratio bandwidth. For the 3-tip (three-tip) step, the resulted bandwidths of respectively impedance, gain, and axial ratio are 1.7%, 3.3% and 0.5%. The pentagonal structure resulted in the bandwith values of 15.67%, 52.16% and 4.11% respectively for impedance, gain, and axial ratio. 

Compact Asymmetric-Slit Microstrip Antennas for Circular Polarization

2011 ◽  
Vol 59 (1) ◽  
pp. 285-288 ◽  
Author(s):  
Nasimuddin ◽  
Xianming Qing ◽  
Zhi Ning Chen
Keyword(s):  
Circular Polarization ◽  
Microstrip Antennas

scholarly journals Analysis of Circular Polarization of Cylindrically Bent Microstrip Antennas

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Tiiti Kellomäki
Keyword(s):  
Simple Model ◽  
Circular Polarization ◽  
Axial Ratio ◽  
Microstrip Antennas ◽  
Far Field ◽  
Circularly Polarized ◽  
Wearable Antennas ◽  
Linearly Polarized ◽  
Frequency Shifting

When circularly polarized (CP) microstrip antennas are bent, the polarization becomes elliptical. We present a simple model that describes the phenomenon. The two linear modes present in a CP patch are modeled separately and added together to produce CP. Bending distorts the almost-spherical equiphase surface of a linearly polarized patch, which leads to phase imbalance in the far-field of a CP patch. The model predicts both the frequency shifting of the axial ratio band as well as the narrowing of the axial ratio beam. Uncontrolled bending is a problem associated especially with flexible textile antennas, and wearable antennas should therefore be designed somewhat conformal.

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