Matlab Code For Radiation Pattern Of Microstrip Patch Antenna
Import the Radiation Pattern Depending on the application, practical phased antenna arrays sometimes use specially designed antenna elements whose radiation pattern cannot be represented by a closed-form equation. In addition, even when the element pattern is well understood, as is the case with a dipole antenna, the mutual coupling among the elements can significantly change the individual element pattern when the element is put into an array. This makes the closed-form pattern less accurate. Thus, for high fidelity pattern analysis, one often needs to use a custom radiation pattern from measurement or simulation. One frequently used full-wave modeling tool for simulating antenna radiation pattern is HFSS™, where the individual element is modeled as if it were part of an infinite array.
Educational Tool for Rectangular and Circular Microstrip Antenna. Radiation pattern of the designed antenna to be. Code-coupled with MATLAB to. Thanks for the code. Can you please help in writing matlab coding for radiation pattern of rectangular microstrip antenna? Antenna microstrip patch wireless. This MATLAB function plots the 3-D radiation pattern of an antenna magnitude, magE over the specified phi and theta angle vectors.
The simulated radiation pattern is represented as an Mx3 matrix whose first column represents angle, second column represents angle, and third column represents the radiation pattern in dB. The coordinate system, or more specifically, the definition of and used in HFSS can be seen in Figure 1a. In this convention, it is assumed that the main beam of the antenna points to the zenith, i.e., the z-axis.
The value of is between 0 and 360 degrees and the value of is between 0 and 180 degrees. Figure 1: Spherical coordinate system convention: a) as used in HFSS, b) as used in Phased Array System Toolbox™.
However, there is no standard convention for the coordinate system used to describe the radiation pattern, so the result from one simulation package may not be directly used in another software package. For example, in Phased Array System Toolbox, the radiation pattern is expressed using azimuth (az) and elevation (el) angles, as depicted in Figure 1b.
More importantly, it is assumed that the main beam of the antenna points toward 0 degrees azimuth and 0 degrees elevation, i.e., the x-axis. The value of az is between -180 and 180 degrees and the value of el is between -90 and 90 degrees. Thus, to use the custom pattern expressed in - convention, we need to find a way to transform such pattern into az-el convention. Here is one possible approach. Scan the Beam An advantage of the phased arrays, compared to a single antenna element, is that the main beam can be electronically steered to a given direction.
This is accomplished by adjusting the weights assigned to each element, also referred to as the steering vector. Each weight is a complex number whose magnitude controls the sidelobe characteristics of the array and whose phase steers the beam.
The next example illustrates the idea of phase steering. The example scans the main beam of the array from -30 degrees azimuth to 30 degrees azimuth, with elevation angle fixed at 0 degrees during the scan. Clear helperPatternScan Radar Vertical Diagram When a radar is deployed in the field, the radiation pattern is modified by the surrounding environment. For example, reflections from the earth may enforce or attenuate the signal arriving at the target via the direct path. In addition, the refraction from the ionosphere can also introduce another path from the top. The resulting pattern in the elevation direction is often quite complicated and a radar engineer often needs to do a rough estimate of the vertical coverage during the system design stage. Lucenzo emigrante del mundo. Next section shows how to estimate the radar vertical diagram, some times also referred to as Blake chart, if the aforementioned array is deployed at a height of 20 meters and covers a free space range of 100 km.
The resulting diagram contains a curve in the space along which the return signal level is a constant. It clearly shows that the main beam is severely modified by the reflection. For example, at a range of 100 km, the return from a target at an elevation angle of 1 degree is much smaller compared to a target at the same range but is at a nearby elevation angle.
The curve also show that for certain angles, a target can be detected at as far as 200 km. This is the case when the reflected signal and the direct path signal are in phase, thus resulting in an enhanced return. Summary This example shows how to construct and analyze an antenna array using a custom antenna pattern. The pattern can be generated using full-wave modeling simulation software with the - convention. The pattern can then be converted to az-el convention.
The resulting array is used to generate a vertical coverage diagram and is also scanned from -30 degrees to 30 degrees in the azimuth direction to illustrate the phase steering concept.
Microstrip Antenna
This example showcases the analysis of an inset-feed patch antenna on a low-epsilon, low-loss, thin dielectric substrate. The results are compared with the reflection coefficient and surface currents around the 2.4 GHz, Wi-Fi band for a reference design 1. The Antenna Toolbox™ library of antenna elements includes a patch antenna model that is driven with a coaxial probe. Another way to excite the patch is by using an inset-feed. The inset-feed is a simple way to excite the patch and allows for planar feeding techniques such as a microstrip line. The Inset-Feed Patch Antenna The inset-feed patch antenna typically comprises of a notch that is cut from the non-radiating edge of the patch to allow for the planar feeding mechanism. Typical feeding mechanism involves a microstrip line coplanar with the patch.
The notch size, i.e. The length and the width are calculated to achieve an impedance match at the operating frequency. A common analytical expression that is used to determine the inset feed position, the distance from the edge of the patch along its length, is shown below 2.
The patch length and width are L, W respectively. Analysis of the Patch Antenna The overall dimensions of this patch antenna are large and therefore will result in a relatively large mesh (dielectric + metal). The structure is analyzed by meshing it with a maximum edge length of 4 mm and solved for the scattering parameters.
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The maximum edge length was chosen to be slightly lesser than the default maximum edge length computed at the highest frequency in the analysis range of 2.45 GHz, which is about 4.7 mm. The analyzed antennas are loaded from a MAT file to the workspace.
Discussion The results for this patch antenna are in good agreement with the reference results reported in 1, pg.111 - 114. Reference 1 Jagath Kumara Halpe Gamage,'Efficient Space Domain Method of Moments for Large Arbitrary Scatterers in Planar Stratified Media', Dept. Of Electronics and Telecommunications, Norwegian University of Science and Technology. 2 Lorena I.
Long, 'The dependence of the input impedance on feed position of probe and microstrip line-fed patch antennas,' IEEE Transactions on in Antennas and Propagation, vol. 1, pp.45-47, Jan 2001. Katehi and N. Alexopoulos, 'Frequency-dependent characteristics of microstrip discontinuities in millimeter wave integrated circuits,' IEEE Transactions on Microwave Theory and Techniques, vol. 1029-1035, 1985.