Frequency Independent Antennas

Spiral Antenna:

Publications:

Zia Ullah Khan, “Simulation Design of Spiral Antenna,” MS Thesis, College of E&ME, NUST, 2009.

Automatic Target Classification

Machine Learning:

A. Javed, S. Liaqat, M. B. Ihsan, "Support vector machine based micro-Doppler signature classification of ground targets" , Radar Conference (EuRAD), 2013, 10th European, Oct. 9 2013 – Oct. 11 2013, pp. 168-171.

, Radar Conference (EuRAD), 2013, 10th European, Oct. 9 2013 – Oct. 11 2013, pp. 168-171. A. Javed, A. Ejaz, S. Liaqat, A. Ashraf, M. B. Ihsan, "Automatic target classifier for a ground surveillance radar using linear discriminant analysis and logistic regression" , in Radar Conference (EuRAD), 2012 9th European, Oct 31 2012-Nov 2, 2012, pp 302-305.

, in Radar Conference (EuRAD), 2012 9th European, Oct 31 2012-Nov 2, 2012, pp 302-305. S. Liaqat, S. A. Khan, A. I. Bhatti, M. B. Ihsan, S. Z. Asghar, A, Ejaz, "Automatic recognition of ground radar targets based on target RCS and short time spectrum variance", in Innovations in Intelligent Systems and Applications 2011 (INISTA 2011), International Symposium on, pp 164-167, Jun 2011.

Joint time-frequency Representation:

S. Liaqat , M. B. Ihsan, S. Z. Asghar , A. Ejaz, A. Javed, "High resolution 2D time frequency representation of radar micro-Doppler pedestrian signal", Radar Conference (EuRAD), 2013, 10th European, Oct. 9 2013-Oct. 11 2013, pp 515-518.

Microwave Systems

Microwave Transmitter Module for Ku Band

Microwave Tranceiver Module for Ku Band

Microwave Receiver Module for Ku Band

Amplifiers

Spatial Power Combining in Rectangular Waveguides using Dense Finline Arrays:

Publications:

M. Anis Chaudhary, “Spatial Power Combining in Rectangular Waveguides using Dense Finline Arrays,” MS Thesis, College of E&ME, NUST, 2010.

High Performance GaN based Switch Mode Class F and Inverse Class F Power Amplifier:

Publications:

Ali Ahmed, “High Performance GaN based Switch Mode Class F and Inverse Class F Power Amplifier,” MS Thesis, College of E&ME, NUST, 2012.

Filters

Substrate Integrated Waveguide Filter:

Publications:

Umar Hasan Khan, “A Narrow Band Subsrate Integrated Waveguide Filter using EM Simulation,” MS Thesis, College of E&ME, NUST, 2013.

Compact UWB Bandpass Filter with High Stopband Rejection:

Publications:

Bilal Aslam, “Packaged Ultra Wide Band Filter,” MS Thesis, College of E&ME, NUST, 2013.

Parallel Coupled Microstrip Bandpass Filter

Publications:

Tahir Abbas, Zubair Ahmed and Mojeeb Bin Ihsan “Parallel Coupled Microstrip Band Pass Filter Design using EM-Analysis”, Proceedings of IEEE INMIC 2004 8th International Multitopic Conference Islamabad Pakistan, 24-26 December 2004, pp 703-705.

Tahir Abbas, Zubair Ahmed and Mojeeb Bin Ihsan. “Design of Coupled-Line Coupled Hairpin-Line Filter Using EM Analysis for Parameter Extraction”, Third International Bhurban Conference on Applied Sciences and Technology, Bhurban, Pakistan, 7-12 June, 2004, pp 740-745.

Archimedean Spiral and Equiangular Spiral Antenna has been designed, simulated and fabricated for the 2GHz to 18GHz bandwidth, |Axial ratio| ≤ 3dB and typical VSWR ≤ 2.15% Reduction in size has been achieved and the parameters of Meander Arm Spiral are better than the classical antenna.We are working on automatic target recognition problem for ground surveillance radar NR-V3. The goal of this research is to develop an automatic target classifier that can classify ground targets detected by NR-V3 radar. The work is based on extracting the micro-Doppler features from the backscattered signal using signal processing and then classifying them using machine learning techniques.In addition, we are developing high resolution 2D time-frequency representation of pedestrian micro-Doppler signature.Scatter plot showing first 3 feature vectors of NR-V3 dataThis work has resulted in a number of publications :Microwave Transmitter Module for Ku BandMicrowave Tranceiver Module for Ku BandMicrowave Receiver Module for Ku BandSpatial power combiners using dense finline arrays (tapered slot antennas) arranged in tray configuration and enclosed in a standard Ku band waveguide (WR-62) have been designed in this work. The design of the finline taper is the most challenging aspect in this work. Before the tapers can be synthesized, a relationship between phase constant of the finline array and its geometrical parameters must be established which can only be achieved through full wave EM analysis. Matlab codes were developed using Spectral Domain Method (SDM) to extract this relationship for single-tray finline, two-tray finline and four-tray finline configuration. Results of SDM codes were also compared with Ansoft HFSS and were found to be in good aggrement. Two tray finline and Four tray finline tapers along with dielectric matching, connected back to back were fabricated and tested using Time Domain Gating feature of Network Analyzer. Results indicate measured return loss of 26.3 dB as compared to simulated return loss of 23.5 dB for single tray finline, 19 dB as compared to simulated return loss of 18.6 dB for two tray finline and 16 dB as compared to simulated return loss of 15.5 dB for four tray finline at 16 GHz.This work is based on design and development of Class AB, Class F and Classpower amplifiers using GaN based transistors. A comparison has been done between these amplifiers based on output power and efficiency. Effect of input harmonic termination on efficiency and output power in Class F and Classpower amplifiers has also been investigated.Inverse Class F designClass F designClass AB designSubstrate integrated waveguide filters at X and Ku band have been designed which involves determining the width of iris as a function of coupling factor. For this purpose, a design curve of iris width vs coupling was generated using HFSS. Two 5 pole Chebyshev bandpass filters have been fabricated on 4003 Rogers. Measured results at 10 GHz presents 380 MHz bandwidth, 6.6 dB insertion loss and return loss better than 12.5 dB. Measured results at 16 GHz presents 410 MHz bandwidth, 8.1 dB insertion loss and return loss better than 13 dB.Thesis research is based on the development of compact UWB bandpass filter for UWB communication in 3.1-10.6 GHz band. Two fourth order UWB filters are designed; one by direct coupling of three E-structures and other by capacitive coupling of two E-structures. Filter based on directly coupled E-shape structures has fractional bandwidth of 97%, maximum flat band insertion loss of 1.3dB, maximum returnloss of 9dB and rejection better than 20dB in GPS band. Chip loaded filterhas fractional bandwidth of 115%, maximum flat band insertion loss of 0.25dB, maximum return loss of 11 dB and rejection better than 25dB in GPS band.Three cascaded E-shape StructureChip Loaded E-shape StructureA fourth order paralled coupled Microstrip band pass filter was designed using chebychev low pass prototype and was simulated on Harmonica and further on EM analysis tool Sonnet to take into account the physical layout and packaging effects. The filter was designed to operate at a centre frequency of 1 GHz and a bandwidth of 200 MHz with pass band ripple of 0.01 dB. The measured results show insertion loss of -1.2 dB and bandwidth of 220 MHz at centre frequency of 1 GHz.