Kam-Weng Tam

Abstract: This article proposes a new design approach for filtering crossovers featuring wide-stopband and dual-band characteristics based on mixed substrate integrated waveguide (SIW) cavities. The degenerate orthogonal modes in multimode full-mode SIW (FMSIW) square cavities are fully exploited as the cross-unit of dual channels for cross-transmission and good isolation. By developing proper coupling topology between multiple quarter-mode SIW (QMSIW) cavities and the FMSIW cavity, a compact wide-stopband filtering crossover is presented with more than −20 dB stopband rejection up to $2.11f_{0}$ . In order to construct a dual-band filtering crossover topology which has not been reported before, half-mode SIW (HMSIW) cavities are explored to cooperate with the FMSIW cavity, thus leading to a satisfactory dual-passband crossover response for the first time. To validate the design concept, a wide-stopband and a dual-band filtering crossovers are designed, fabricated, and measured. Results exhibit excellent filtering performance and good channel-to-channel isolations over an ultrawide frequency band.

TL;DR: It is shown that the proposed power allocation schemes can achieve significant power savings when compared with fixed power allocation, and under practical low outage constraint, the power efficiency is further improved when the time correlation is reduced and/or the fading order is increased.

TL;DR: A prediction model is created and presented to study the radiation level from mobile telephony base-station antennas using electromagnetic (EM) field simulation and the results illustrated the whole region is within the radiation exposure threshold given by ICNIRP radiation safety standard.