A Simple Design and Analysis of Coaxial Fed Annular Ring Microstrip Patch Antenna For Wireless Communication Systems
Forschungsarbeit 2014 5 Seiten
In this paper design and analysis of annular or circular ring type microstrip patch antenna and the basic terms related to design aspects and study of proposed antenna is presented. Like many available variations of microstrip patch geometries annular or circular ring widely used due to its broadband nature when operated in mode and has smaller circular counterparts when it is operated in its fundamental mode . In this article theoretical and mathematical analysis related to annular ring patch antenna with design is presented and briefly explained. The designed antenna operates at 2.4 GHz resonant frequency so can be used in ISM (Industrial, Scientific and Medical) band wireless applications. The proposed antenna shows good return loss, VSWR as depicted in the graphs.
Keywords: Microstrip Patch Antennas (MSAs), Circular Ring Microstrip Patch Antenna (CRMSA), Annular Ring Microstrip Patch Antenna (ARMSA), Circular Polarization, Voltage Standing Wave Ratio (VSWR)
Microstrip patch antenna (MSA) consists of metallic or conducting strip on dielectric substrate covered by ground plane on other side and patch radiates fringing fields around its edges . For miniaturization of communication equipment compact microstrip patch antennas (MSAs) have been much attracted due to its light weight and light volume and better performance. However, microstrip patch antennas have limitation of narrow bandwidth which limits its application in practice  but there are so many techniques available to improve the performance of patch antennas. The geometries of patch antenna like rectangular, circular disk, triangular etc. are available and their variation such as rectangular ring, semi circular disk, annular ring are used for some wireless and communication applications. Also as an alternative to regular or standard rectangular and circular patch antenna rectangular ring and circular ring or annular ring patch antenna are widely used because of their broadband nature and these configuration are smaller in size as compared to prior configurations so size will be less as compared to its rectangular or circular counterparts . These antennas are low-profile, simple and inexpensive to manufacture using printed circuit technology [4-7].
The annular ring structure is a good resonator for modes (where m is odd) (with very little radiation), and it will be good radiator for modes (where m is even) .
There are several good features are associated with this patch configuration viz. when operated in its lowest mode size of this antenna is small then circular patch antenna so in array application size of overall antenna will be quite small. Secondly it is possible to combine annular ring with second microstrip element and thirdly the separation of the modes can be controlled by ratio of outer to inner radii and by operating in one of the higher-order broadside modes, i.e. the impedance bandwidth is several times larger than is achievable in other patches (rectangular or circular etc. patch configurations) of comparable dielectric thickness . Figure 1 and figure 2 depict proposed geometry of annular ring patch antenna structure. The outer and inner radii are and respectively as shown in figure.
illustration not visible in this excerpt
Figure 1 : Proposed Antenna Geometry: Antenna Dimensions Substrate Height Patch thickness