03ELD030 :: FINAL YEAR PROJECT Asymmetric CoPlanar Strip Antenna Optimiser Student Mr Daniel Birkett (9932043) Course MEng Electronic & Electrical Engineering Ext. Supervisor Dr J A Flint

Asymmetric CoPlanar Strip Asymmetric CoPlanar Stripline Asymmetric Strips S1,S2 have unequal widths: W1!=W2 CoPlanar Conductors in the same plane Asymmetric CoPlanar Strip Antenna Optimiser

Asymmetric CoPlanar Strip Abstract The aim of the project was to create a tool to aid the design of Asymmetric CoPlanar Strip antennas Uses of such antennas can be found in equipment including mobile communications. The asymmetric coplanar folded dipole is an appealing choice for two primary reasons: It can be constructed using printed circuit technology Its input impedance can be made to match that of printed circuit transmission lines. The input impedance depends on three quantities: The impedance of the transmission line mode The impedance of the dipole mode The impedance step-up ratio. The project proposal was set by Dr J A Flint, who required an application to simplify the analysis required in antenna design as part of his research in wireless systems. The project itself focusing around use with 3rd Generation, 3G operating frequencies Asymmetric CoPlanar Strip Antenna Optimiser

Asymmetric CoPlanar Strip Objective(s) “Develop a computer based system capable of analysing the properties of asymmetric coplanar strip antennas using principally physical dimensions”  Validate theoretical design equations through full field quasi-static simulations, using Finite Element Analysis software. Evaluate unknown electrical characteristics using antenna modelling software. Design software modules to implement theoretical calculations for arbitrary parameters. Create a Graphical User Interface to consolidate software modules and display appropriate analytical information. Asymmetric CoPlanar Strip Antenna Optimiser

Objective (1) :: Characteristic Impedance Validate theoretical design equations through full field quasi-static simulations, using Finite Element Analysis software. ACPS full field simulation Simulation interacting with boundary The capacitance can be calculated by either using the energy stored or charge. The equation to calculate the characteristic impedance is The characteristic impedance calculated through the theoretical design equations is within 6% of the value calculated through FEA Asymmetric CoPlanar Strip Antenna Optimiser

Objective (2) :: Dipole Impedance Evaluate unknown electrical characteristics using antenna modelling software. The computer program AWAS for Windows (Analysis of Wire Antennas and Scatterers) is capable of analyzing wire antennas operating in the transmitting and receiving modes, as well as analyzing wire scatterers. The technique is based on the two-potential equation for the distribution of wire currents. This integro-differential equation is solved numerically, using the method of moments with a polynomial (power-series) approximation for the current distribution The analysis method requires only a small number of polynomial coefficients (about 6 to 9 per wavelength). It can analyze structures up to about 100 wavelengths in total wire length. The program can analyze arbitrary structures that are assembled from straight-line wire segments (of circular cross sections). Each wire segment is assumed to have its own radius. Each segment connects two points in space, referred to as nodes. Each node is defined by three Cartesian coordinates (x,y,z) “The kernel of the program can be used on a stand-alone basis, or it can be incorporated into a user-written program, such as an optimization procedure for antenna synthesis” Asymmetric CoPlanar Strip Antenna Optimiser

Objective (3) :: Calculation Flow Design software modules to implement theoretical calculations for arbitrary parameters. The input impedance depends on three quantities: The impedance of the transmission line mode The impedance of the dipole mode The impedance step-up ratio. Asymmetric CoPlanar Strip Antenna Optimiser

Objective (4) :: ACPS Optimiser Create a Graphical User Interface to consolidate software modules and display appropriate analytical information. Asymmetric CoPlanar Strip Antenna Optimiser

Asymmetric CoPlanar Strip Conclusion From the objectives set: all have been completed successfully. The tool created, greatly simplifies the design process by a magnitude. The tool provides a GUI which rivals the older AWAS shell Future devolvement could be extended in numerous ways, including: Admittance and scattering parameters The presence of a conducting ground plane or a dielectric Specific wave data - The system is capable of analysing the impedance properties of a folded dipole antenna using its physical dimensions. It evaluates the unknown electrical characteristics via utilising AWAS’ numerical kernel and, uses software modules to implement the theoretical calculations for arbitrary parameters. As well as providing a Graphical User Interface to consolidate the software modules and display appropriate analytical information. Although utilising only a fifth of the kernel capability (due to the project specifications): the tool, uniquely, implements this successfully. - The numerical kernel is capable of analysing antennas in far greater detail than required of it within the project objectives (specific wave data) plane waves, near and far field wave information. Asymmetric CoPlanar Strip Antenna Optimiser

Asymmetric CoPlanar Strip Any Questions Asymmetric CoPlanar Strip Antenna Optimiser