Designed end to end model for computing the phase correction error factor and 3D simulation model for properties ofreflect arrays and parabolic reflectors to calculate phase difference of patch elements using High performance clusters, whichserves as reference for antenna fabrication to ensure stable Transmission and Reception.
Technologies Used:MATLAB, Simulink, Python, and Ansys HFSS
Description
Motive of this project is to simulate the properties of an Antenna such that it gives the phase difference in which the elements need to be manufactured such that the Antenna provides stable Transmission and Reception.
Tool : MATLAB r2021a.
1 OVERVIEW
2 OBJECTIVE
3 PRODUCTION
4 REFERENCES
In telecommunications and radar, a reflective array antenna is a class of directive antennas in which multiple driven elements are mounted in front of a flat surface designed to reflect the radio waves in a desired direction. They are a type of array antenna. They are often used in the VHF(30-30MHz) and UHF(30MHz-3GHz) frequency bands. VHF examples are generally large and resemble a highway billboard, so they are sometimes called billboard antennas. Other names are bedspring array and bowtie array depending on the type of elements making up the antenna. The curtain array is a larger version used by shortwave radio broadcasting stations.
Reflective array antennas usually have a number of identical driven elements, fed in phase, in front of a flat, electrically large reflecting surface to produce a unidirectional beam of radio waves, increasing antenna gain and reducing radiation in unwanted directions. The larger the number of elements used, the higher the gain; the narrower the beam is and the smaller the sidelobes are. The individual elements are most commonly half wave dipoles, although they sometimes contain parasitic elements as well as driven elements. The reflector may be a metal sheet or more commonly a wire screen. A metal screen reflects radio waves as well as a solid metal sheet as long as the holes in the screen are smaller than about one-tenth of a wavelength, so screens are often used to reduce weight and wind loads on the antenna. They usually consist of a grill of parallel wires or rods, oriented parallel to the axis of the dipole elements. A Reflect Array antenna consists of a planar or conformal array of elements that are excited with a feed antenna. Each element is designed such that when it is illuminated by the feed antenna, it incorporates a certain reflected phase. The phase distribution over the Reflect Array aperture is then synthesized so the Reflect Array can realize a collimated or shaped beam in the desired direction. As such, analysis and design of the Reflect Array elements, typically referred to as phasing elements, is of paramount importance. One problem associated with feedhorns is the shadow introduced by the feedhorn if it is in the path of the beam. The shadow is a dead spot directly in front of the feedhorn. Normally the feed horn constitutes an obstruction for the rays coming from the reflector at a parabolic antenna.
To solve this problem the feedhorn can be offset from center. In an offset feed, the feed is outside the path of the wave so there is no pattern deterioration due to aperture blocking. The horn faces upwards relative to the axis of the parabola and the lower half of the parabola is removed. The net effect is that the parabola is shallower with a larger focal length. The feed horn is therefore situated further from the reflector and requires greater directivity to avoid spill over of energy. This design therefore requires larger horns and is generally more difficult and expensive to construct.
Most radars with a parabolic antenna are using the principle of offset antenna. This structure also has the advantage in radar devices that the high transmit power is not reflected directly back to the radiator. The radiator would receive back this power: thus, the standing wave ratio would deteriorate on the line to the antenna. Therefore, the load of the transmitter's end stage is lower using an offset antenna.
To generate a MATLAB code in such a way that it yields the phase distribution over the OFFSET-Fed Reflect Array aperture is then synthesized so the Reflect Array can realize a collimated or shaped beam in the desired direction.
There are two steps in the design of a Reflect Array, namely, the element design and the system design. In other words, how the individual elements are designed to scatter electromagnetic waves with the desired phases. Moreover, numerical and analytical approaches for analysis of Reflect Array phasing elements will be outlined, and several examples of Reflect Array phasing elements will be presented.
The side view of an offset Reflect Array system showing the edge and feed subtended angles such that it does not obstructs the Collimatedbeam thereby maintaining the Gain. Shown in figure 3.
- Reflectarray Antennas by John Huang ,Jose Antonio Encinar.
- Reflectarray Antennas Theory, Designs, and Applications (Wiley - IEEE)1st Edition by Payam Nayeri , Fan Yang ,Atef Z. Elsherbeni.
- REFLECTARRAY ANTENNAS: A review Eduardo Carrasco (1) and Jose A. Encinar (2) (1) Foundation for Research on Information Technologies in Society (IT’IS) (Email: [email protected]) (2) Universidad Politécnica de Madrid (Email: [email protected])
- ACES Journal :The Analogy between Offset Configurations of Parabolic Reflectors and Reflectarrays :Payam Nayeri , Atef Z. Elsherbeni , and Fan Yang.