Applied Mechanics and Materials Vol. 763

Abstract: A triplexer is an important component for channel separation in microwave front-end systems. This paper proposes a triplexers designed with common dual mode resonator sections have been proposed. By exploiting the variable frequency response of the stepped-impedance resonator, resonators can be shared by the three filter channels of the desired triplexer if their fundamental and the first spurious resonant frequency are properly assigned. Triplexer design method for suppressing spurious responses in the stopband by choosing the constitutive resonators with the same fundamental frequency, but staggered higher order resonant frequencies. The design concept is demonstrated by three of third order parallel-coupled bandpass filters. The bandpass filter is composed of three different stepped impedance resonators for which a general design guideline had been provided in order have the same fundamental frequency and different spurious frequencies. The measured results are in good agreement with the simulated predictions, whereby the spurious responses in the upper stopband can be suppressed below-25dB up to 14 GHz, which can be quite useful for multiband and multiservice applications in future wireless communication systems.

Abstract: Shifter has been used in encoder of structured low density parity check (LDPC) codes due to the nature of its structure. Single clock cycle time of shifter is selected for doing matrix-vector multiplication of LDPC encoding to minimize encoding latency. Among the shifters which complete the multiplication within one clock cycle, this paper suggests the cyclic shifter for structured LDPC encoder. It is shown that the implementation of the typical cyclic shifter has less logic gates and less bit controller than the other shifter.