Miniaturised and reconfigurable planar filters for ultra-wideband applications

Rabbi, K.M.F. 2014. Miniaturised and reconfigurable planar filters for ultra-wideband applications. PhD thesis University of Westminster Faculty of Science and Technology

TitleMiniaturised and reconfigurable planar filters for ultra-wideband applications
TypePhD thesis
AuthorsRabbi, K.M.F.
Abstract

An increasing demand for electromagnetic spectrum has resulted from the emergence of feature-rich and faster throughputs wireless applications. This necessitates the developments of dynamic reconfigurable or multifunctional systems to better exploit the existing spectrum.

Future wireless devices will be expected to communicate over several bands with various other devices in order to fine tune the services they provide to the user. Each band may require a separate RF transceiver and such modern wireless multi-band multi-mode communication systems call for high performance, highly integrated compact modules. Since the Federal Communications Commission (FCC) released the unlicensed frequency band 3.1-10.6 GHz for ultra-wideband (UWB) commercial communications, the

development race for commercialising UWB technology has seen a dramatic increase around the world.

The aim of this research is to develop reconfigurable planar microwave filters for ultrawideband applications. The project investigates some key design issues of reconfigurable

filters, which are being observed constantly in the latest development and realisation of microwave filters. Both analytical and numerical methods are performed to construct a realistic and functional design. Two different types of frequency reconfigurability are investigated in this thesis: discrete (e.g. PIN diode, Optical switch) and continuous (e.g. varactor diode). Using the equivalent circuits and considering the direct coupled filter structure in most cases, several topologies with attractive features are developed for future communication systems. The proposed works may be broadly categorised into three

sections as follows.

The first section explores a square ring shape close loop resonator along with an opencircuited stub in the symmetry plane. To realise a reconfigurable frequency states within the same spectrum, an innovative approach is developed for this case. An optical or

photoconductive switch, comprised of a silicon die activated using near infrared light is investigated as a substitute of PIN diode and performances are evaluated to compare the feasibilities. In addition, a in-band interference rejection technique via externally coupled Tshape resonator is shown. However, it is observed that both structures achieve significant size reductions by utilising the inner part of the resonators.

To improve the filter selectivity, a convenient design approach generating a pair of transmission zeros between both passband edges and a single zero in the stop band for harmonic suppression is discussed in the second section. Moreover, the development of notched rejection bands are studied and several novel methods to create a single and multiple notched bands employing the square ring shape structure are proposed. On inspection, it is found that the notch structure can be implemented without deteriorating the filter performances. The discussions are supplemented with detailed design examples which are accompanied by theoretical, simulated and experimental results in order to illustrate the filter development process and showcase practical filter performance. The third section reveals a novel highly compact planar dual-mode resonator with sharp rejections characteristics for UWB applications. A bandwidth reconfiguring technique is demonstrated by splitting its even-mode resonance. Filter structure with the dual-mode resonator is shown to have a relatively wide tuning range, significantly low insertion loss and a constant selectivity along with frequency variations in comparison to similar published works. Finally, the earlier dual-mode structure are modified to realise a dual wideband behaviour. A detail analysis with comprehensive design procedures is outlined and a solution for controlling the frequency bandwidths independently according to the application interest is provided. In line with the previous section, experimental verification is presented to support and supplement the discussions.

Year2014
FileKhondker_RABBI_2014.pdf
Publication dates
Completed2014

Related outputs

Highly selective reconfigurable filter for UWB systems
Rabbi, K.M.F. and Budimir, D. 2014. Highly selective reconfigurable filter for UWB systems. IEEE Microwave and Wireless Components Letters. 24 (3), pp. 146-148. doi:10.1109/LMWC.2013.2291857

Evaluation of nonlinear distortion in optically switchable UWB filters
Chakrabarty, K., Rabbi, K.M.F., Panagamuwa, C., Kodogiannis, V. and Budimir, D. 2014. Evaluation of nonlinear distortion in optically switchable UWB filters. Microwave and Optical Technology Letters. 56 (5), pp. 1092-1094. doi:10.1002/mop.28277

Highly linear microstrip wideband bandpass filter with switchable notched band for wireless applications
Rabbi, K.M.F., Athukorala, L., Panagamuwa, C., Vardaxoglou, J.C. and Budimir, D. 2013. Highly linear microstrip wideband bandpass filter with switchable notched band for wireless applications. Microwave and Optical Technology Letters. 55 (6), pp. 1331-1335. doi:10.1002/mop.27585

Compact UWB bandpass filter with reconfigurable notched band
Rabbi, K.M.F., Athukorala, L., Panagamuwa, C., Vardaxoglou, J.C. and Budimir, D. 2013. Compact UWB bandpass filter with reconfigurable notched band. Electronics Letters. 49 (11), pp. 709-711. doi:10.1049/el.2012.3555

High linearity microstrip bandpass filter with electronically tunable notch
Rabbi, K.M.F., Athukorala, L. and Budimir, D. 2013. High linearity microstrip bandpass filter with electronically tunable notch. Microwave and Optical Technology Letters. 55 (2), pp. 418-421. doi:10.1002/mop.27312

Miniaturized dual-mode microstrip bandpass filters with a reconfigurable notched band for UWB applications
Rabbi, K.M.F. and Budimir, D. 2013. Miniaturized dual-mode microstrip bandpass filters with a reconfigurable notched band for UWB applications. 2013 IEEE MTT-S International Microwave Symposium (IMS2013). Seattle, WA, USA 2 – 7 June 2013 doi:10.1109/MWSYM.2013.6697586

Miniaturised sharp rejection bandpass filter with reconfigurable bandwidth for UWB applications
Rabbi, K.M.F. and Budimir, D. 2013. Miniaturised sharp rejection bandpass filter with reconfigurable bandwidth for UWB applications. 43rd European Microwave Conference (EuMC2013). Nuremberg, Germany October 6-11, 2013 pp. 1023-1026

Linearity evaluation of optically reconfigurable UWB microstrip bandpass filter
Chakrabarty, K., Rabbi, K.M.F., Panagamuwa, C., Vardaxoglou, J.C. and Budimir, D. 2013. Linearity evaluation of optically reconfigurable UWB microstrip bandpass filter. 2013 IEEE International Symposium on Antennas and Propagation and USNC-URSI Nnational Radio Science Meeting. Lake Buena Vista, Florida, USA. July 7-12, 2013

Optically reconfigurable CPW filters for UWB applications
Rabbi, K.M.F. and Budimir, D. 2012. Optically reconfigurable CPW filters for UWB applications. IEEE International Symposium on Antennas and Propogation and CNC//USNC/URSI National Radio Science Meeting (APS2012). Chicago, Illinois, USA 08 - 14 July 2012 IEEE . doi:10.1109/APS.2012.6348654

High-linearity reconfigurable microstrip UWB bandpass filters
Rabbi, K.M.F., Athukorala, L., Panagamuwa, C., Vardaxoglou, J.C. and Budimir, D. 2011. High-linearity reconfigurable microstrip UWB bandpass filters. 41st European Microwave Conference (EuMC). Manchester, UK 09 - 14 Oct 2011 pp. 172-175

Simulation of reconfigurable WLAN notch for UWB filters
Rabbi, K.M.F., Anand, A., Athukorala, L. and Budimir, D. 2011. Simulation of reconfigurable WLAN notch for UWB filters. IEEE International Symposium on Antennas and Propogation (AP-S) and 2011 USNC/CNC/URSI National Radio Science Meeting. Spokane, Washington, USA 03 - 08 Jul 2011

Optically reconfigurable microstrip UWB bandpass filters
Athukorala, L., Rabbi, K.M.F., Panagamuwa, C., Vardaxoglou, J.C., Philippakis, M. and Budimir, D. 2010. Optically reconfigurable microstrip UWB bandpass filters. in: IEEE Loughborough Antennas and Propagation Conference (LAPC2010), 8-9 November 2010, Loughborough IEEE . pp. 617-620

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