Course Calendar - CEI-Europe
September 27 - 29, 2017. Amersfoort, The Netherlands
Low loss and highly selective filters and multiplexers are key components in the wireless networks that surround us. A low loss diplexer allows the transmitter and receiver of a basestation to simultaneously share the same antenna. The same filter must also guarantee that co-located basestations using competing transmission standards do not interfere with each other. Many of these filters and multiplexers are based on cavity combline technology, which is relatively simple to manufacture. Others are based on dielectric resonator (DR) technology that can realize a high quality factor (Q) filter in a smaller volume. Introducing non-adjacent couplings (cross-couplings) into a microwave filter can generate transmission zeros in the lower and or upper stopbands. It is the filter order and the clever placement of these transmission zeros that generates the selectivity needed for wireless applications. The theory of cross-coupled filters was first introduced in the 1960's. It was then adopted for satellite multiplexer applications in the 1970's and for wireless applications in the following decades. EM simulation is also an essential component of modern cavity filter design. We now have the ability to model and optimize complete filter structures in the EM domain. These virtual prototypes have greatly reduced the number of hardware prototypes that must be built and tuned. Occasionally, we find unexpected spurious couplings in our virtual EM prototypes that prevent us from tuning the filter to the desired response. These spurious couplings would be very difficult and expensive to diagnose after the hardware is built.
 

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