oThe MAT codes obtain a solution by solving surface and volume integral equations via the method of moments (MOM) oIn MOM, the current on metals and the fields in dielectrics are approximated by special functions (basis functions) defined over sub-domains or sub- regions on/near the antenna oThe currents are approximated over triangular sub- domains defined on metal surfaces while the fields are approximated in tetrahedrons defined in the dielectric around the antenna oThese triangles & tetrahedrons define a mesh or grid which represents an electromagnetic/numerical model of the antenna oMeshes with many triangles and tetrahedrons result in large memory and computer-time requirements oOne must be careful to ensure a representative and sufficiently refined mesh to get useful numerical solutions that can be used to accurately predict characteristics of real-world antennas Ground Plane Shorting Strip Probe feed L- shaped slit BACKGROUND oGraduate students usually use Ansoft HFSS for antenna modeling oToo complicated and expensive for undergrads oA much easier and user-friendly code has been developed by Makarov (Worcester Polytechnic Institute) called the Matlab Antenna Toolbox (MAT) oThe code is reasonably precise for simple printed antennas PRINTED ANTENNAS NUMERICAL SOLUTION VIA INTEGRAL EQUATION AND MOM NUMERICAL SOLUTION VIA INTEGRAL EQUATION AND MOM ANTENNA I Design oThis is a Planar Inverted-F Antenna (PIFA) oRectangular patch = 36x16 mm 2 oL-Shaped slit width = 1 mm oShorting strip width = 2.5 mm oGround plane = 18x80 mm 2 oAir substrate present between the patch and ground plane Matlab 3D model Aerial View Return Loss Convergence Study oThe return loss was plotted for 70 frequency points with a frequency range of GHz oA finer mesh was used each time Input Impedance oFound with 3292 triangle mesh oResonant frequencies are approx. 1.9 and 2.3 GHz oPrinted antennas are low-profile planar structures that utilize printed circuit board (PCB) technology oThey are compact, low cost, easy to manufacture and suitable for integration with electronic systems oMulti-band operation can also be achieved by integrating several coupled printed antenna elements of different lengths and geometries on the same PCB oDimension can be smaller with higher dielectric oUses: GPS, Radar, Satellite communication, Military, cell phones, and wireless laptops Triangular meshTetrahedron grid Directivity oAt 1.9 GHz the max. directivity is approx. 3.5 dB oAt 2.3 GHz the max. directivity is approx. 1.2 dB Return Loss Convergence Study oThe return loss was plotted for 50 frequency points oA finer mesh was used each time oComputation times ranged from 40 to 180 mins Surface Currents oThe magnitude of surface currents are calculated at 1.9 and 2.3 GHz Patch 1.9 GHz Patch 2.3 GHz ANTENNA II Design oThis is a microstrip-fed wide-slot antenna oSquare patch = 110x110 mm 2 oWide slot = 53.7x53.7 mm 2 oMicrostrip = 31.5x1.5 mm 2 oGround plane = 110x110 mm 2 o0.8 mm thin FR4 substrate (ε r =4.4) present between the patch and ground plane 1.9 GHz 2.3 GHz Patch Dielectric Microstrip Matlab 3D modelAerial View Directivity oAt 1.67 GHz the max. directivity is approx. 4.5 dB Input Impedance oResonant frequency is approx GHz FUTURE WORK oSimulate more multiband antennas accordingly with future wireless communication needs oIncorporate the genetic algorithm with the code for antenna optimization oAfter convergence studies construct and test a multiband antenna in the spherical near field chamber Patch