Introduction to Efficiently Modeling Antennas in COMSOL MultiphysicsTo keep our antenna modeling process efficient and accurate, we should start with a simple geometry and then gradually add more complex features. The final simulation needs to include enough detail to accurately represent our design, while excluding elements that needlessly increase the computational cost. To demonstrate this, we look at an anechoic chamber example, which is used to characterize antenna performance, before examining how this process applies to several antenna examples available in the COMSOL Multiphysics software. Patch Antenna Impedance Formula' title='Patch Antenna Impedance Formula' />International Journal of Engineering Research and Applications IJERA is an open access online peer reviewed international journal that publishes research. The most common type of microstrip antenna is the patch antenna. Antennas using patches as constitutive elements in an array are also possible. Designing Antennas in Anechoic Chambers. Since antennas radiate electromagnetic waves, it is important to ensure that their radiated fields dont return to the radiating source. The absorbers attached to the chambers walls play a major role in this process by absorbing incident waves on their surfaces. This makes the anechoic chamber a key aspect in an antenna simulation. However, including the anechoic chamber is challenging because it increases the simulations computational requirements. A biconical antenna excited in an anechoic chamber, used to test for electromagnetic interference EMI and electromagnetic compatibility EMC. The anechoic chamber shown above is smaller than the typical anechoic chamber that meets CISPR specifications, but its computational cost is still high. This model requires over 1. GB of RAM. To improve computational efficiency, we should simplify the model, while maintaining the accuracy of the computation. As discussed in a previous blog post, we can accomplish this by using a perfectly matched layer PML. The Yaesu FT901DM FT902DM. Yaesu FT901DM Transceiver Yaesu FT. After operating for more than 10 years in the antenna, satellite TV and communications industry, Access Antennas Australia has expanded with shops Australiawide. Test Parameters. Many of the measurements are reported in decibels dB and are calculated by using the following formulas The standard unit for the gain or loss of. Ali_El_Alami/publication/267448837/figure/fig10/AS:295544795746315@1447474778970/Figure-14-Input-impedance-of-the-patch-antenna-as-a-Function-of-frequency.png' alt='Patch Antenna Impedance Formula' title='Patch Antenna Impedance Formula' />This reduces the memory use to less than 2 GB without sacrificing simulation accuracy. How to Set Up an Antenna Model in COMSOL MultiphysicsTo efficiently mimic the real world in our antenna simulation, we need to choose the correct boundary conditions and physics features. Accurately reflecting real world conditions in your simulation environment, while still keeping your model memory and time efficient, can be challenging. In the table below, we outline some real world antenna scenarios and the optimal modeling feature to choose. Simulation Environment. Anechoic chamber absorbing electromagnetic waves. Scattering boundary condition. Perfectly matched layer. Metallic antenna body and surface. A major component of a wireless LAN system is the antenna. There are several different types and they all have their place. However, there can be some confusion. Perfect electric conductor. Impedance boundary condition. Transition boundary condition. Network analyzer measuring S parameters for antenna input matching properties. Port or lumped port. Numeric TEM port. Network analyzer or spectrum analyzer measuring far field radiation pattern. Patch-Antenna-Calculator.jpg' alt='Patch Antenna Impedance Formula' title='Patch Antenna Impedance Formula' />Computer controlled measurement turntable. Far field domain and calculation. When setting up an antenna model, you do not need many complicated boundary conditions. You can actually build an antenna in COMSOL Multiphysics by deploying only four features. Lets see how to do this with a printed dipole antenna example. The geometry of a printed dipole antenna. A printed dipole antennas geometry consists of four objects. Polystyrene foam board. Printed metallic layer. The geometry is configured with only two materials a user defined polystyrene foam board and the air that encloses the simulation domain. Use the following table to choose the correct physics features. Physics Feature. Perfect Electric Conductor boundary condition. Mimics metallic surfaces with a high conductivity. Patch Antenna Impedance Formula' title='Patch Antenna Impedance Formula' />Excites the antenna and measures S parameters. Scattering boundary condition. Absorbs the incident wave to minimize any reflection. Far field domain and calculation. Calculates the far field radiation pattern, directivity, and gain. A Perfect Electric Conductor boundary condition imposed on a rectangular strip. For the intended operating frequency, the simulation may only take a few seconds. The RF Module provides the default S parameter evaluation, electric field distribution plot, and polar far field plot. It also gives you the 3. D far field radiation pattern plot, which shows the computed directivity and gain. The far field radiation pattern of a printed dipole antenna. The computed directivity is 2. B, which is close to that of an ideal half wave dipole antenna. Although simulating an antenna is a straightforward process, it is a good idea to start with a simple structure, whether you are a beginner or an expert. This way, you can ensure that the basic modeling process is correct for the simple geometry before adding complex design elements. Torrent Cubase Pro 8 Mac here. The RF Module also enables you to combine electromagnetics with any other type of physics. You can see and change all of the physics features in the modeling environment and clearly define every physics property. Taking into account multiple physical effects, as well as knowing the underlying physics involved, is useful when validating your antenna design. To capture the details of the physics, such as the loss on metallic surfaces, the Perfect Electric Conductor boundary condition can be replaced by the Transition boundary condition for a geometrically very thin lossy layer or an Impedance boundary condition for surfaces of a lossy volume. You can also use a PML instead of a Scattering boundary condition, which assumes that the incident wave is normal to the surface. After setting up these physics features, you can begin to design your antenna, whether its shape is traditional, wideband, multiband, or an array. Designing a Variety of Antennas with the RF Module. You can access many antenna examples for a wide range of applications in the Application Library in the RF Module. The tutorial models range from conventional antennas, such as half wave dipole and microstrip patch antennas, to wideband and multiband antennas, including Vivaldi, fractal, spiral, and helical antennas. There is also an antenna array example, which can be useful when designing devices for the 5. G mobile network. Traditional Antenna Examples. Traditional antennas, like the half wave dipole and microstrip patch antenna shown below, are good examples to start with when learning how to model antennas in the COMSOL Multiphysics software. Their geometries are relatively easy to build and its simple to validate the results with well known analytical solutions. For example, you can simulate a half wave dipole antenna to find its omnidirectional radiation. Or, you can model a microstrip patch antenna to see if the electric field is confined to the radiating edges. Conventional antennas half wave dipole antenna with a quarter wave coaxial balun left and microstrip patch antenna right. Wideband and Multiband Antenna Examples. Sometimes, we need to cover many different frequency ranges with a single antenna. Windows 7 Iso The Pirate Bay La. By tweaking the radiating structure and using the multiple resonance behaviors of a certain part of the metallic body or slot, we can meet the systems specifications without deploying multiple antennas. One such example is the popular Vivaldi antenna, also called a tapered slot antenna. Using fractal algorithms, such as those from Sierpinski, Koch, and Hilbert, you can generate interesting results for antenna applications. For instance, unlike the half wave dipole antenna, which can only be used for a single frequency resonance, the Sierpinski fractal antenna doesnt require additional matching networks to adjust the antenna input impedance to the reference characteristic impedance of 5. Wideband and multiband antennas Vivaldi antenna left and Sierpinski fractal monopole antenna right. Antenna Array Examples.