This paper proposes the design of two circular driven yagi patch antennas with elliptical elements which are placed on two different substrates. These antennas operate at a frequency of 2.45GHz which comes under the WLAN frequency range. The main objective of the paper is to transmit the physiological information of a person to the monitoring stations. The proposed antennas are designed and simulated using FEKO.
Index Terms -YPA, FEKO, Circular driven, CYPAE, RYPAE.
Telemetry is a communication system where information is transmitted from the living system to the monitoring station. Telemetry applications can also be extended for monitoring astronaut’s health condition ...view middle of the document...
It has unidirectional beam of moderate directivity which can be enhanced by using patch antenna. It’s a fixed frequency device i.e., frequency sensitive . Patch antennas can have a square, rectangular, circular, triangular or elliptical shape. The size of the patch antenna is inversely proportional to frequency. A hole is formed through the ground plane and through the dielectric to allow access to the bottom surface of the patch . The dielectric substrate has a ground plane on one side and a conducting patch on the other side which can be either planar or non-planar .
III. ANTENNA GEOMETRY
The prototype of the proposed antennas differ only by the shape of the substrates i.e., RYPAE and CYPAE. The antennas have a circular active element and elliptical passive elements (i.e., reflectors, directors and extra coupling elements) that are coupled to each other. The spacing between the driven element and the other passive elements is small so as to enable better coupling between the elements.
A. Circular Driven Rectangular YPA with elliptical elements
The first proposed model is the circular driven rectangular YPA with elliptical elements. This antenna has the yagi patch antenna’s placed in the rectangular substrate. In this the substrate is rectangular in shape. Fig.1 gives the proposed model.
Fig. 1 Proposed RYPAE
B. Circular Driven Circular YPA
The second proposed model is the circular driven circular YPA with elliptical elements. In this the substrate is circular in shape. Fig.2 gives the proposed model.
Fig. 2 Proposed CYPAE
C. Design Parameters
The following table, Table I gives the design parameters value for the proposed antennas.
ANTENNA DESIGN PARAMETERS
S.NO Parameter RYPAE CYPAE
1 Operating Frequency 2.45 GHz 2.46 GHz
2 Dielectric Constant 4.4 4.4
3 Substrate Thickness 0.85mm 0.85mm
4 Substrate Dimensions 63mm X 63mm 36mm
5 Ground Thickness 0.5mm 0.5mm
6 Ground Dimensions 63mm X 63mm 36mm
7 Driven element radius 17mm 17mm
8 Reflector Dimensions 5mm X2.5mm 5mm X 2.5mm
9 Director Dimensions 5mm X2.5mm 5mm X 2.5mm
10 Extra- Coupling element Dimensions 12.5mm X 2.5mm 12.5mm X 2.5mm
IV. SIMULATED AND MEASURED RESULTS
The proposed antennas which were designed and simulated using FEKO and the following results are obtained.
A. Radiation Pattern
The following fig 3 and fig 4 shows the radiation pattern of RYPAE and CYPAE respectively.
Fig. 3 Radiation Pattern of RYPAE