Uppsala universitet
Radio Frontend Integration Techniques:
CAD Models and Applications

Dhanesh G-Kurup

Licentiate Thesis, Signals and Systems, Uppsala University, December 2000.


Abstract:
The thesis treats the electromagnetic CAD modeling of some important components useful for designing multilayered radio front-ends and active antennas. The models developed are flexible to use and computationally efficient for optimization together with active circuits.

The steps leading to the development of accurate CAD models of antennas suitable for designing active antennas is presented. We considered edge fed and aperture coupled microstrip antennas. The implementation of the program is based on accurate cavity and transmission line models. The CAD models of the antenna are also extended to incorporate micro-machined antennas. Simulations are compared with real experiments.

An efficient method for analysis of slots in the ground plane of transmission lines based on a spectral domain method is also introduced. The application of non-resonant slots in the matching of microwave amplifiers showed improved noise and gain characteristics when compared to traditional transmission line matching techniques.

Based on transverse resonance techniques CAD models of sandwich-slotlines were developed. Simulations indicate good performance for silicon based sandwich-slotlines. Nonradiative dielectric (NRD) connectors is another interesting candidate for designing multilayered integrated circuits. The coupling between NRD connectors and microstrip lines is studied by incorporating a transmission line model. Moreover a dual polarised NRD plug based antenna structure is presented.

Flexibility of use is one important design issue considered in the development of the models. Since object oriented programming is used in the development of the CAD models, the models of different components can be coupled by means of powerful optimization tools and active circuit simulators.


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