Diversity in PCS antenna systems

This paper discusses the issues involved in introducing antenna diversity techniques into a PCS antenna design system. Various diversity strategies are described, ranging from diversity in signal processing to antenna diversity. Examples showing how a system simulator may be employed to characterize the system performance in terms of SNR, BER, etc in the time domain and intermodulation, harmonic distortion and spectral re-growth in the frequency domain. The paper focuses upon the use of a commercial 3D simulator (with parametric and optimisation capabilities) to quantify the effectiveness of various antenna diversity techniques. These range from spatial, pattern, and polarization diversity to transmit/receive diversity. The case studies use the planar inverted F-antenna (PIFA) to illustrate these techniques. The 3D simulator is used to generate design curves from which a set of antenna dimensions can be selected to produce a design which will resonate at a selected frequency and have a specified bandwidth. A capacitive variable (a metal plate on PIFA) is adjusted to tune the antenna performance and the 3D simulator is used to compute the antenna performance in each case. The paper also shows how a circuit simulator is used to rapidly match the antenna input impedance to its feed line by using an embedded Smith chart tool to design the matching networks.