Impedance Transformation Networks: My past research focused on the design and implementation of dual and tri-band impedance matching networks (IMN). Since low frequency-ratio and transformation-ratio were bottlenecks for the successful implementation of dual and tri-band IMN, my Ph.D. thesis works dealt with improving these figures-of-merit by proposing novel and advanced IMN configurations. Specifically, my thesis reported the discovery of some fundamental properties of multi-section transmission lines and their applications in the realization of improved IMN. Some novel concepts, such as load-healing were also proposed to tackle this problem. These original concepts were applied in the design of advanced RF/microwave passive components such as couplers and power dividers. My current work in this area focuses on the generalization of these theories for a truly multi-frequency scenario and in designing wideband matching networks with application to power dividers and amplifiers.
Highly Efficient Multi-band RF Rectifier for Energy Harvesting/ Wireless power transfer: During my postdoctoral training at the University of Calgary, I focused on RF energy harvesting. The motivation is to be able to supply power to low-energy devices in the wireless sensor networks and wearable electronics that form the backbone of Internet-of-Things (IoTs). Manual maintenance of billions of these low-energy consuming nodes is humanly impossible, therefore, being able to wirelessly power them from ambient RF radiation is a very promising approach. Unfortunately, the current state-of-the-art RF rectifiers have very low RF-to-DC conversion efficiency. My research aims at designing highly efficient RF rectifiers for such applications using novel circuit and/or system topologies, especially targeting multi-band scenarios.
Wideband Power Amplifiers for 5G and Beyond: Besides continuing my current research directions, my future work will primarily focus on the wideband design of RF power amplifiers for 5G applications and beyond. Successful deployment of 5G technologies demands very wide bandwidth RF/microwave power amplifiers that can operate with extremely high efficiency. To design a highly efficient power amplifier, properly terminating impedance not only at the fundamental frequency, but also at harmonic frequencies is very crucial, and is quite a challenging job. Device modeling is also a major step towards de-embedding parasitics leading to access to the device plane. Furthermore, efficiency enhancement at power back-off level is crucial due to advanced modulation schemes which necessitate dealing with high peak-to-average power ratio (PAPR) signals such as those in the Orthogonal-Frequency Division Multiplexing (OFDM). This requires a thorough study and advancement of architectures like Doherty power amplifiers. In addition, my plan is to work on tunable passive components useful in RF amplifiers such as tunable RF filters and power combiners.
Low-cost Education/Teaching Platforms Employing Microcontrollers: (To be updated)
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