Workshop/Tutorial

Teguh Firmansyah (Universitas Sultan Ageng Tirtayasa)

Microwave sensors (MS) have been the subject of intensive study and development in both academic and industrial circles due to their numerous advantages such as high sensitivity, high selectivity, and ease of fabrication. These sensors operate based on radio frequency (RF) signals, detecting changes in the environment and subsequently shifting the frequency, phase, amplitude, or reflection values. Several proposed MS have only monofunctional capability. In contrast, to support the development of IoT technology, multifunctional sensors are needed. The development of multifunctional MS structures faces several major challenges: 1) They exhibit a high degree of complexity, requiring additional insulator structures between the device and the MS. 2) They require an additional power supply to support the various functionalities. 3) They typically support only a single-band communication system with a fixed band, which limits their versatility and compatibility. 4) Many proposed multifunctional devices offer switchable functionalities, meaning that only one feature can be active at a given time. This constraint prevents the simultaneous operation of multiple functions, potentially reducing efficiency and causing inconvenience. 5) In some cases, the different functions integrated within a combined device may not operate independently. The performance of one function may be affected by the operation of another, leading to compromised performance and unpredictable behavior. 6) The ambiguous and non-independent characteristics of multifunctional devices often introduce uncertainties regarding their performance and limitations. It can be challenging to precisely define their capabilities and ensure consistent performance across all functionalities. Consequently, the challenges in developing more agile and versatile multifunctional MS/devices are numerous, leaving many voids and open problems to address. Therefore, this tutorial will explain several strategies to develop multifunctional sensors, including the cross-sectional effect. The subsections include hybrid MS and Localized Surface Plasmon Resonance (LSPR) sensors, hybrid MS with attenuators, and hybrid MS with dual-band bandpass filters.

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Dr. Nasimuddin (I2R, Singapore)

Dr. Mohammad Hashmi (Nazarbayev University, Kazakhstan)

Global demand for energy has grown rapidly in recent years. To meet the long-term demand for global energy, different techniques of wireless energy harvesting have been introduced. Harvesting RF energy is an alternative solution, especially with the advances and popularity of wireless communication devices. These communication devices are constantly transmitting RF energy, so RF energy harvesting paves a way to utilize the abundant scattered electromagnetic (EM) waves in our surrounding environment. The available EM waves (RF energy) can be in any polarization, such as elliptical, linear, or circular. By using an appropriate receiving antenna, EM waves can be converted into electrical energy for low-powered devices, and thus, there is much focus put toward RF energy-harvesting (RFEH) systems, especially in receiving antenna designs. A receiving circularly polarized antenna enables the system to harvest RF energy regardless of the device orientation, as well as making the system insensitive to polarization loss. The RF waves/energy that is found in the surrounding area can exist in any orientation/polarization, so dual circularly polarized antennas or dual polarized antennas are more desirable for energy harvesting systems. The first part of tutorial talk will elaborate on all these aspects and recent advancements in the antenna technologies for RFEH systems. The compact and low-profile circularly polarized antenna designs will also be presented in detail for RFEH system demonstrations.

Furthermore, the emergence of low power sensor nodes and biomedical applications has necessitated the requirements of seamless battery charging techniques. Apparently, these functionalities can be facilitated by wireless power transfer (WPT) technology. The WPT assists users to rid of inconvenient wires and facilitates powering and charging the devices’ batteries. The WPT systems have the potential to bring a complete turnaround in a variety of applications. They have been lately employed in a number of segments such as biomedicine, consumer electronics, low-power deceives, and wireless technologies. WPT can be broadly classified as far- (radiative) and near-field (non-radiative) types. Over the last decades, there has been an increase in the employment of near-field WPT systems in a variety of evolving applications that demand miniature and robust wireless end modules (i.e., resonating antennas). One such emerging application is found in biomedicine, where WPTs are critical due to their ability to charge implants without the use of inconvenient and unsafe cables. This clearly calls for the design and realization of a small-size WPT capable of coping with the low-power regime. To cater to the requirements of such applications, the exploitation of the slotted ground plane (SGP)-based WPT systems has recently piqued interest. In general, the SGP method allows reducing the resonator area, resulting in the realization of ultra-compact WPTs. Apparently, the existing multiple challenges of SGP-type WPTs necessitate efficient trade-offs for the best achievable outcome. The second part of tutorial talk will take the audience through the fundamentals of near-field WPT systems to the advanced design techniques and associated applications.

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Florinel Balteanu (Skyworks Solutions Inc, Irvine, CA, USA)

The research field focused on enhancing the performance, cost-effectiveness, and size of 5G radio frequency (RF) solutions, as well as its evolution to 6G, is highly active with numerous developments. It serves as a driving force for the semiconductor industry to reduce transistor feature size, decrease current consumption, and increase speed. By 2022, the number of mobile cellular subscribers has surpassed 6 billion and 5G technology enables high data capacity with low latency through sub-6GHz and mm-Wave spectrum. In future 6G networks, mm-Wave up to 300GHz will play a significant role. The widespread use of smartphones globally has been made possible in part thanks to advancements in CMOS technology at lower feature nodes such as 3nm/5nm, which have greatly improved computational power. This progress has also allowed for enhanced RF CMOS through digital signal processing (DSP) and digital calibration. The smartphone industry operates on a massive scale where hardware changes and improvements require thorough testing for functionality and reliability before being deployed in high volume. This short course will cover the present designs of 5G RF front-end modules used in RF cellular technologies, as well as the obstacles presented by the implementation of 5G and its future progression to 6G. The course will offer a thorough examination of practical 5G RF implementation and the latest advancements in next-generation mobile applications.

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Eng Leong Tan (Nanyang Technological University)

This short course will introduce new fundamental equations of electromagnetics (EM) that replace Maxwell’s fields/potentials with single physical quantity unifying all electrostatics, magnetostatics, electrodynamics and quantum-EM interactions. Since Maxwell-Hertz-Heaviside era, the longstanding dilemma to use either fields or potentials and which gauge for electromagnetics will be discussed. The concept and utilization of field-impulses will then be shown to not only resolve such century-old field-potential/gauge dilemma, but also aptly describe quantum-EM (e.g. Aharonov-Bohm) effects. Theoretical formulation and efficient computation with fundamental implicit schemes of finite-difference-time-domain methods will be presented. Several mobile apps for technology-enhanced-learning of electromagnetics and circuits will also be demonstrated.

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Markus Lörner (Market Segment Manager at Rohde & Schwarz)

This workshop offers a deep dive, how precise load pull measurements support the optimization of RF power amplifiers in the D-band, a frequency range gaining momentum with its growing range of applications. Our session will center around a latest multi-stage power amplifier design operating in D-band. We will explore the distinctions and applications of passive versus hybrid load pull techniques, highlighting their roles in advanced measurement scenarios. The performance verification of RF power amplifiers will include CW and extreme wideband modulated scenarios. Collaborating with Friedrich Alexander Universität Germany, Focus Microwaves and MPI Corporation, we present a comprehensive view of D-Band measurement challenges and solutions, addressing the practical and theoretical aspects vital for advancing in this evolving technology sphere.

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Fabrizio De Paolis (European Space Agency, University of Surrey)

Gabriele Gradoni (University of Surrey)

The integration of satellite communication (SATCOM) and terrestrial 5G systems is currently an active topic of research and undergoes intense standardization activity. The satellite systems have the potential to not only solve coverage problems but also boost capacity in hot spots. This integration enables interoperability, as well as joint signal design and supply chain that in its turn reduces overall operating costs. This course focus on the RF/Microwave aspects of such integration, including both passive technologies (e.g., filtering for satellite/terrestrial co-existence) and active technologies (e.g., using 5G New Radio over satellite links and corresponding changes needed in the standard). The course will also discuss the role of Reconfigurable Intelligent Surfaces (RIS) in satellite/terrestrial integrated systems towards 6G.

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