Open Access
Silicon-based 0.450-0.475 THz series-fed double dielectric resonator on-chip antenna array based on metamaterial properties for integrated-circuits
(IEEE, 2019) Alibakhshikenari, Mohammad; Virdee, Bal S.; See, Chan H.; Abd-Alhameed, Raed; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
The antenna array designed to operate over 0.450-0.475 Terahertz comprises two dielectric resonators (DRs) that are stacked vertically on top of each other and placed on the surface of the slot antenna fabricated on a silicon substrate using standard CMOS technology. The slot created in the silicon substrate is meandering and is surrounded by metallic via-wall to prevent energy dissipation. The antenna has a maximum gain of 4.5dBi and radiation efficiency of 45.7% at 0.4625 THz. The combination of slot and vias transform the antenna to a metamaterial structure that provides a relatively small antenna footprint. The proposed series-fed double DRs on-chip antenna array is useful for applications in THz integrated circuits.
Open Access
Study on improvement of the performance parameters of a novel 0.41–0.47 THz on-chip antenna based on metasurface concept realized on 50 μm GaAs-layer
(Nature Research, 2020) Alibakhshikenari, Mohammad; Virdee, Bal S.; See, Chan H.; Shukla, Panchamkumar; Falcone Lanas, Francisco; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A feasibility study is presented on the performance parameters of a novel on-chip antenna based on metasurface technology at terahertz band. The proposed metasurface on-chip antenna is constructed on an electrically thin high-permittivity gallium arsenide (GaAs) substrate layer. Metasurface is implemented by engraving slot-lines on an array of 11 × 11 circular patches fabricated on the top layer of the GaAs substrate and metallic via-holes implemented in the central patch of each row constituting the array, which connects the patch to the leaky-wave open-ended feeding slot-lines running underneath the patches. The slot-lines are connected to each other with a slit. A waveguide port is used to excite the array via slot-lines that couple the electromagnetic energy to the patches. The metasurface on-chip antenna is shown to exhibit an average measured gain in excess of 10 dBi and radiation efficiency above 60% over a wide frequency range from 0.41 to 0.47 THz, which is significant development over other on-chip antenna techniques reported to date. Dimensions of the antenna are 8.6 × 8.6 × 0.0503 mm3. The results show that the proposed GaAs-based metasurface on-chip antenna is viable for applications in terahertz integrated circuits.
Open Access
Impedance bandwidth improvement of a planar antenna based on metamaterial-inspired T-matching network
(IEEE, 2021) Alibakhshikenari, Mohammad; Virdee, Bal S.; Shukla, Panchamkumar; Wang, Yan; Azpilicueta Fernández de las Heras, Leyre; Naser Moghadasi, Mohammad; See, Chan H.; Elfergani, Issa; Zebiri, Chemseddine; Abd-Alhameed, Raed; Huynen, Isabelle; Rodriguez, Jonathan; Denidni, Tayeb A.; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this paper a metamaterial-inspired T-matching network is directly imbedded inside the feedline of a microstrip antenna to realize optimum power transfer between the front-end of an RF Wireless transceiver and the antenna. The proposed T-matching network, which is composed of an arrangement of series capacitor, shunt inductor, series capacitor, exhibits left-handed metamaterial characteristics. The matching network is first theoretically modelled to gain insight of its limitations. It was then implemented directly in the 50-Ω feedline to a standard circular patch antenna, which is an unconventional methodology. The antenna’s performance was verified through measurements. With the proposed technique there is 2.7 dBi improvement in the antenna’s radiation gain and 12% increase in the efficiency at the center frequency,and this is achieved over a significantly wider frequency range by a factor of approximately twenty. Moreover, there is good correlation between the theoretical model, method of moments simulation, and the measurement results.
Open Access
A new study to suppress mutual-coupling between waveguide slot array antennas based on metasurface bulkhead for MIMO systems
(IEEE, 2018) Alibakhshikenari, Mohammad; Virdee, Bal S.; Khalily, Mohsen; See, Chan H.; Abd-Alhameed, Raed; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, a new method is proposed to reduce mutual coupling between waveguide slot array (WSA) antennas based on metasurface technology. This is achieved by placing a metasurface bulkhead between the two WSA antennas. Performance of the dual-waveguide antenna structure is shown to substantially enhance when compared against an identical reference WSA antenna with no metasurface. WSA antennas used in the study has dimensions 40×20×5mm 3 and operates over 1.7-3.66 GHz, which corresponds to a fractional bandwidth of 73.13%. The average isolation of the reference WSA antennas is -20 dB; however, with a metasurface bulkhead the isolation is shown to increase to -36.5 dB. In addition, the bandwidth extends by ~10%, and the gain improves by 14.66%. The proposed method is should find application in MIMO systems where high isolation between neighbouring radiation elements is required to improve the antenna characteristics, and mimimise array phase errors, which is necessary to enhance the system performance.
Open Access
Low-cost multiband four-port phased array antenna for sub-6 GHz 5G applications with enhanced gain methodology in radio-over-fiber systems using modulation instability
(IEEE, 2024-08-19) Zakeri, Hassan; Azizpour, Rasul; Khoddami, Parsa; Moradi, Gholamreza; Alibakhshikenari, Mohammad; See, Chan H.; Denidni, Tayeb A.; Falcone Lanas, Francisco; Koziel, Slawomir; Limiti, Ernesto; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
Phased array antenna (PAA) technology is essential for applications requiring high gain and wide bandwidth, such as sensors, medical, and 5G. Achieving such a design, however, is a challenging and intricate process that calls for precise calculations and a combination of findings to alter the phase and amplitude of each unit. Furthermore, coupling effects between these PAA structure elements can only be completed with the use of full-wave electromagnetic simulation tools. Due to recent advances, radio-over-fiber (RoF) technology has been positioned as a possible alternative for high-capacity wireless communications. This paper presents a low-cost, multiband Sub-6 GHz 5G PAA with enhanced gain achieved through integration with a new specialized RoF system design to improve PAA performance by using the phenomenon of modulation instability (MI). Optimizing the antenna’s Defected Ground Structure (DGS) leads to even more improvement. To enable operation across three distinct frequency bands (Sub6 GHz n78 band (3-3.8 GHz), n79 band (3.8-5 GHz), and n46 band (5-5.5 GHz)), the proposed antenna design features four elliptical patches strategically positioned at the four sides of the ground plane, providing comprehensive 360◦ coverage in the azimuth plane. Additionally, integrating elliptical slots and upper gaps contributes to improvement. The proposed PAA’s experimentally validated gain values are 5.2 dB, 7.4 dB, and 7.8 dB in the n78, n79, and n46 bands, respectively. For improving the performance of the proposed PAA in RoF systems, anomalous fibers (n2 ̸= 0 and β2 < 0) are employed to consider the modulation instability (MI) phenomenon, which can lead to the generation of the MI gain on the carrier sideband. The true time delay (TTD) technique controls the beam pattern by adjusting the time delay between adjacent radiation elements. Furthermore, the TTD technique utilizes frequency combs for the proposed 4-element array antenna to apply MI gain to all antenna elements.
Open Access
Optimum power transfer in RF front end systems using adaptive impedance matching technique
(Nature Research, 2021) Alibakhshikenari, Mohammad; Virdee, Bal S.; Azpilicueta Fernández de las Heras, Leyre; See, Chan H.; Abd-Alhameed, Raed; Althuwayb, Ayman Abdulhadi; Falcone Lanas, Francisco; Huynen, Isabelle; Denidni, Tayeb A.; Limiti, Ernesto; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Matching the antenna’s impedance to the RF-front-end of a wireless communications system is challenging as the impedance varies with its surround environment. Autonomously matching the antenna to the RF-front-end is therefore essential to optimize power transfer and thereby maintain the antenna’s radiation efficiency. This paper presents a theoretical technique for automatically tuning an LC impedance matching network that compensates antenna mismatch presented to the RF-front-end. The proposed technique converges to a matching point without the need of complex mathematical modelling of the system comprising of non-linear control elements. Digital circuitry is used to implement the required matching circuit. Reliable convergence is achieved within the tuning range of the LC-network using control-loops that can independently control the LC impedance. An algorithm based on the proposed technique was used to verify its effectiveness with various antenna loads. Mismatch error of the technique is less than 0.2%. The technique enables speedy convergence (< 5 µs) and is highly accurate for autonomous adaptive antenna matching networks.
Open Access
An antenna array utilizing slotted conductive slab: inspired by metasurface and defected ground plane techniques for flexible electronics and sensors operating in the millimeter-wave and terahertz spectrum
(Springer, 2023) Ali, Esraa Mousa; Alibakhshikenari, Mohammad; Virdee, Bal S.; Kouhalvandi, Lida; Livreri, Patrizia; Falcone Lanas, Francisco; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper describes an innovative design of an antenna array that is metamaterial inspired using sub-wavelength slots and defected ground structure (DGS) for operation over millimeter-wave and terahertz (THz) spectrum. The proposed antenna array consists of a 2 × 4 array of conductive boxes on which are implemented rectangular slots. The presence of dielectric slots introduces resonant modes within the structure. These resonant modes result in enhancing the electromagnetic fields within the slots, which radiate energy into free space. The resonant frequencies and radiation patterns depend on the specific geometry of the slots and the dielectric properties. The antenna array is excited through a single microstrip line. The radiating elements in the array are interconnected to each other with a microstrip line. Unwanted mutual coupling between the radiating elements can degrade the performance of the antenna. This was mitigated by defecting the ground plane with rectangular slots. It is shown that this technique can enhance the array¿s reflection coefficient over a wider bandwidth. The array was constructed on polyimide substrate having dielectric constant of 3.5 and thickness of 20 ¿m. The design was modelled, and its performance verified using an industry standard electromagnetic package by CST Studio Suite. The proposed array antenna has dimensions of 20 × 10 mm2 and operates between 80 and 200 GHz for radiation gain better than 4 dBi and efficiency above 55%. The peak radiation gain and efficiency are 7.5 dBi and 75% at 91 GHz, respectively. The operational frequency range of the array corresponds to a fractional bandwidth of 85.71%.
Open Access
Wideband printed monopole antenna for application in wireless communication systems
(IET, 2018) Alibakhshikenari, Mohammad; Virdee, Bal S.; See, Chan H.; Abd-Alhameed, Raed; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Empirical results of an electrically small printed monopole antenna are described with a fractional bandwidth of 185% (115 MHz to 2.90 GHz) for return-loss better than 10 dB, peak gain and radiation efficiency at 1.45 GHz of 2.35 dBi and 78.8%, respectively. The antenna geometry can be approximated to a back-to-back triangular shaped patch structure that is excited through a common feed-line with a meander-line T-shape divider. The truncated ground-plane includes a central stub located underneath the feed-line. The impedance bandwidth of the antenna is enhanced with the inclusion of meander-line slots in the patch and four double split-ring resonators on the underside of the radiating patches. The antenna radiates approximately omni-directionally to provide coverage over a large part of very high frequency, the whole of ultrahigh frequency, the whole of L-band and some parts of S-band. The antenna has dimensions of 48.32 × 43.72 × 0.8 mm 3 , which is corresponding to the electrical size of 0.235 λ 0 × 0.211 λ 0 × 0.003 λ 0 , where λ 0 is the free-space wavelength at 1.45 GHz. The proposed low-profile low-cost antenna is suitable for application in wideband wireless communications systems.
Open Access
Optical-microwave sensor for real-time measurement of water contamination in oil derivatives
(Elsevier, 2023) Abdulsattar, Rusul K.; Alibakhshikenari, Mohammad; Virdee, Bal S.; Sharma, Richa; Elwi, Taha A.; Kouhalvandi, Lida; Hassain, Zaid Abdul; Ali, Syed Mansoor; Türker Tokan, Nurhan; Livreri, Patrizia; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper presents a novel microwave sensor using optical activation for measuring in real-time the water contamination in crude oil or its derivatives. The sensor is constructed from an end-coupled microstrip resonator that is interconnected to two pairs of identical fractal structures based on Moore curves. Electromagnetic (EM) interaction between the fractal curves is mitigated using a T-shaped microstrip-stub to enhance the performance of the sensor. The gap in one pair of fractal curves is loaded with light dependent resistors (LDR) and the other pair with microwave chip capacitors. The chip capacitors were used to increase the EM coupling between the fractal gaps to realize a high Q-factor resonator that determines the sensitivity of the sensor. Empirical results presented here show that the insertion-loss of the sensor is affected by the change in LDR impedance when illuminated by light. This property is used to determine the amount of water contaminated oil. The sensitivity of the sensor was optimized using commercial 3D EM solver. The measurements were made by placing a 30 mm diameter petri dish holding the sample on top of the sensor. The petri dish was filled up to a height of 10 mm with the sample of water contaminated crude oil, and the measurements were done in the range between 0.76 GHz and 1.2 GHz. The Q-factor of the oil sample with no water contamination was 70 and the Q-factor declined to 20 for 100% contamination. The error in the measurements was less than 0.024%. The sensor has dimensions of 0.127λo × 0.127λo × 0.004 λo and represents a new modality. Compared to existing techniques, the proposed sensor is simple to use, readily portable and is more sensitive.
Open Access
A comprehensive survey of 'metamaterial transmission-line based antennas: design, challenges, and applications'
(IEEE, 2020) Alibakhshikenari, Mohammad; Virdee, Bal S.; Azpilicueta Fernández de las Heras, Leyre; Naser Moghadasi, Mohammad; Falcone Lanas, Francisco; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this review paper, a comprehensive study on the concept, theory, and applications of composite right/left-handed transmission lines (CRLH-TLs) by considering their use in antenna system designs have been provided. It is shown that CRLH-TLs with negative permittivity (< 0) and negative permeability (μ < 0) have unique properties that do not occur naturally. Therefore, they are referred to as artificial structures called 'metamaterials'. These artificial structures include series left-handed (LH) capacitances (CL), shunt LH inductances (LL), series right-handed (RH) inductances (LR), and shunt RH capacitances (CR) that are realized by slots or interdigital capacitors, stubs or via-holes, unwanted current flowing on the surface, and gap distance between the surface and ground-plane, respectively. In the most cases, it is also shown that structures based on CRLH metamaterial-TLs are superior than their conventional alternatives, since they have smaller dimensions, lower-profile, wider bandwidth, better radiation patterns, higher gain and efficiency, which make them easier and more cost-effective to manufacture and mass produce. Hence, a broad range of metamaterial-based design possibilities are introduced to highlight the improvement of the performance parameters that are rare and not often discussed in available literature. Therefore, this survey provides a wide overview of key early-stage concepts of metematerial-based designs as a thorough reference for specialist antennas and microwave circuits designers. To analyze the critical features of metamaterial theory and concept, several examples are used. Comparisons on the basis of physical size, bandwidth, materials, gain, efficiency, and radiation patterns are made for all the examples that are based on CRLH metamaterial-TLs. As revealed in all the metematerial design examples, foot-print area decrement is an important issue of study that have a strong impact for the enlargement of the next generation wireless communication systems.