Riana Geschke

Design of Microstrip Lossy Filter Using an Extended Doublet Topology

A lossy three-pole microstrip bandpass filter using an extended doublet network is proposed in this letter. Nonuniform Q distribution is considered by reducing the Qu of one resonator, resulting in a flatter passband with an enhanced selectivity. Also, the novel feeding network adopted brings about two extra transmission zeros and a wide stopband that further improve the filter performance. Good agreement between the simulated and measured results can be observed to validate the design.

Mu-near-zero propagation in quasi-TEM microstrip circuits

This paper presents the theoretical analysis and experimental demonstration of mu-near-zero (MNZ) propagation in quasi-TEM microstrip circuits achieved by using metamaterials of the resonant type. We show that two frequencies exist which may support MNZ propagation and how the actual operating of MNZ frequency depends on the properties of the host. The phenomena of MNZ propagation is then used to propose an entirely new class of MNZ bandpass filters characterized by significantly reduced variation of group delay in comparison to conventional solutions.

The MTT-S Region 8 Coordinator's Visit to South Africa [Around the Globe]

July/August 2017 In the IEEE Microwave Theory and Techniques Society (MTT-S) overview on the Society’s web page, we find these two opening sentences: The MTT-S is a transnational society with more than 10,500 members and 190 Chapters worldwide. Our Society promotes the advancement of m icrowave theory and its applications, including RF, microwave, millimeter-wave, and terahertz technologies. The sentiments expressed here were fully realized during MTT-S Region 8 Coordinator Jan Machac’s visit to South Africa at the invitation of the South Africa MTT-S/IEEE Antennas and Propagation Society (APS)/IEEE Electromagnetic Compatibility (EMC) Society Joint Chapter. Prof. Machac was welcomed by two universities, beginning his visit on 13 February 2017 in Pretoria and ending on 17 February 2017 in Cape Town. ■ Riana Geschke, Jan Machac, and Tinus Stander The MTT-S Region 8 Coordinator’s Visit to South Africa

Dual-band filters with independent passbands based on perturbed grounded patch resonators

In this paper, two novel dual-band filters with independent passbands are proposed, which operate according to the IEEE 802.11b/g/n standard. The filters are based on a rectangular grounded patch, modified by introducing an edge slot perturbation. In that way, separate control of the couplings at both operating frequencies of the filter is achieved, resulting in independent control of both the position and the bandwidths of two filters passbands.