Slow-Wave Substrate-Integrated Waveguide (eBook)

Designing of Devices and Antennas

Jing-Ya Deng, Jia-Yuan Yin, Fengxia Li, Yulong Liu, Li-Xin Guo, Xiao-Hua Ma (Autoren)

eBook Download: EPUB

2025
321 Seiten
Wiley-IEEE Press (Verlag)
978-1-394-31419-5 (ISBN)

Infos

Comprehensive text on the fundamentals of systematic design methods and analysis for slow-wave substrate integrated waveguide

Enriched with practical examples and illustrations, Slow-Wave Substrate-Integrated Waveguides introduces the application of slow-wave substrate-integrated waveguides in miniaturized and integrated antennas. The book details the advantages of microstrip lines and metal waveguides, with low cost, low loss, and easy-to-integrate with planar circuits, delves into slow wave structure in the design of antennas and devices, allowing for additional distributed capacitors and inductors, and discusses how to overcome the technical challenges associated with miniaturizing slow wave microwave devices and antennas.

Topics explored in this book include:

• The potential for larger multi-beam antennas to improve communication system capacity
• Devices such as couplers, miniaturized phase shifters, and waveguide cross-junctions
• Antennas such as bidirectionally-fed slow-wave substrate-integrated waveguide monopulse slot array antennas and miniaturized H-plane horn antennas with ?30 dB sidelobes
• Transmission lines, beamforming networks, and future perspectives in the field

Slow-Wave Substrate-Integrated Waveguides is an essential reference for students and professionals in the fields of physics, optics, electromagnetics, communications seeking to improve the spectrum efficiency, energy efficiency, and cost efficiency of wireless communication systems.

Jing-Ya Deng, PhD, is a Professor at the School of Physics, Xidian University, China.

Jia-Yuan Yin, PhD, is an Associate Professor at the School of Physics, Xidian University, China.

Fengxia Li, PhD, is a Lecturer at the School of Physics, Xidian University, China.

Yulong Liu, is a Senior Engineer with China Research Institute of Radiowave Propagation, China.

Li-Xin Guo, PhD, is a Professor with the School of Physics, Xidian University, Xi'an, China.

Xiao-Hua Ma, PhD, is a Professor with the School of Microelectronics, Xidian University, China.

Textauszug

1
Background

1.1 Research Background

The evolution of wireless communication has experienced significant changes since 1901 [1], particularly with the transition from the 1G–4G Internet of People (IoP) to the current 5G Internet of Everything (IoE) and the anticipated integration of air, earth, and sea communication systems. This transformation has revolutionized communication methods, significantly enhanced communication efficiency, stimulated industrial advancement, and advanced the development of societal information infrastructure. Recent advancements in wireless communication technology have instigated higher demands for channel capacity, integration, and miniaturization of communication systems [2, 3]. Thus, microwave devices are mandated to achieve miniaturization and high integration by reducing circuit size and implementing a planar structure.

Antennas, as devices for receiving and radiating radio signals, play an essential part in the overall effectiveness of wireless communication systems. To improve communication rates, minimize communication delays, and ensure communication quality, it is imperative to enhance the signal‐to‐noise ratio at user terminals. However, wireless communication is susceptible to obstacles such as building occlusions, multipath fading, and severe weather conditions, leading to a reduction in the signal‐to‐noise ratio at the user terminal. When increasing the transmitting power is not feasible, high‐gain directional antennas can be utilized to enhance the signal‐to‐noise ratio. Nevertheless, the narrow beamwidth of high‐gain antennas restricts their coverage [4]. To address the challenge of reconciling high gain with broad coverage, multi‐beam antennas [5–10] can generate multiple high‐gain directional beams, each pointing in a different direction, thereby expanding coverage.

According to their technological system, multi‐beam antennas may be divided into three types: active digital multi‐beam antennas, phased array multi‐beam antennas, and passive multi‐beam antennas [11]. Phased array multi‐beam antennas necessitate numerous adjustable phase shifters, with each antenna unit or subarray requiring connection to a radio frequency (RF) channel. This system, however, is complex and costly [12]. In contrast, active digital multi‐beam antennas require intricate beamforming algorithms to achieve phase weighting of signals received or transmitted by each antenna unit in the digital domain, imposing stringent demands on the calculation and processing capabilities of baseband processors [13]. In contrast, passive multi‐beam antennas do not necessitate a large number of adjustable phase shifters or complex beamforming algorithms; the beam can be controlled by toggling the RF switch. This approach entails simple processing and low costs. The beamforming network, a critical component of passive multi‐beam antennas used to generate multiple high‐gain directional beams, includes a typical beamforming network known as the Butler matrix. Only a cascade design of microwave components, such as phase shifters, directional couplers, cross‐junctions, and antenna radiation units based on certain topological features, is needed for the Butler matrix. Upon exiting each input port, a high‐gain directional beam can be generated correspondingly, offering the benefits of a straightforward structure, easy design, and low loss [14].

The current trend toward miniaturization and integration of modern wireless communication systems necessitates the design of antennas to be in line with the principles of miniaturization and integration. Given that multi‐beam antennas require miniaturization due to the larger size of the beamforming network, the Butler matrix—composed of basic microwave components such as couplers, cross‐junctions, and phase shifters [15]—can be miniaturized to reduce its physical size, thereby meeting the miniaturization design requirements of the entire multi‐beam antenna. In addition, antenna radiation units and beamforming networks might be designed using the substrate‐integrated waveguide (SIW), which has been suggested recently, to make it easier to integrate multi‐beam antennas with other planar circuits [16]. The SIW combines the benefits of metallic waveguides with microstrip lines, offering low loss, low processing costs, and seamless integration with planar circuits. Furthermore, to further enhance the miniaturization of multi‐beam antennas, the introduction of the slow‐wave structure (SWS) into antenna and device designs could be beneficial. The SWS shortens the waveguide wavelength, increases the equivalent relative permeability and permittivity, decreases the phase velocity of the electromagnetic wave on the transmission line, and essentially reduces the size of antennas and microwave devices by adding more distributed capacitance and inductance.

Metallic waveguides were first proposed in 1936 [2]; however, their application was limited due to their high machining cost and nonplanar structure, which hindered integration. In 1952, the microstrip transmission line was introduced, enabling the planarization of waveguide structures and improving system integrability. Nevertheless, its semi‐open structure resulted in high transmission loss. The gap waveguide structure has become a novel waveguide design in recent decades. It achieves electromagnetic shielding by connecting an artificial magnetic conductor (AMC) and a perfect electric conductor (PEC) in parallel. This novel technology offers low loss, exhibits good electromagnetic compatibility characteristics, and is suitable for the microwave–millimeter‐wave field. The gap waveguide exhibits similar electromagnetic characteristics to metallic waveguides and possesses unique advantages compared to traditional metallic waveguides.

Despite its numerous advantages, the gap waveguide is larger than the traditional microstrip circuit, which contradicts the demand for miniaturization in communication systems. While research on SIW, a structure similar to the gap waveguide, has explored various methods for miniaturization, there has been limited research on miniaturizing gap waveguides. Therefore, the realization and miniaturization design of the gap waveguide hold significant research and practical value.

In the context of current mobile communication, achieving high spectral efficiency for 4G and 5G networks is essential. However, various factors, such as noise, multipath fading, and spectrum congestion, significantly affect efficiency improvement. With the increasing demand for miniaturization, single antennas can no longer meet this need, and the available space for antennas has reduced considerably. Consequently, traditional technologies are inadequate. New technologies, such as multiple‐input multiple‐output (MIMO) technology, have been developed to solve the issue. A key challenge of MIMO technology is enhancing antenna performance within a limited area and mitigating the coupling effect between multiple antenna elements. Therefore, designing MIMO antennas with high isolation in a confined space, by combining antenna miniaturization methods and wideband requirements, is a research problem of significant value that needs to be addressed.

In summary, as a crucial component of wireless communication systems, the performance of microwave–millimeter‐wave antennas and devices directly influences the overall system performance. Therefore, researching and designing miniaturized and integrated antennas and devices based on SWS holds great significance in enhancing the spectral efficiency, energy efficiency, and cost efficiency of wireless communication systems.

1.2 Research Status

1.2.1 Slow‐Wave Transmission Line

The slow‐wave (SW) transmission line is formed by introducing an SWS onto the ordinary transmission line. This introduced SWS enhances the distributed capacitance and inductance effects of the transmission line, effectively increasing the permeability and dielectric constant equivalents of the dielectric substrate. This, in turn, reduces the propagation phase velocity of electromagnetic waves on the transmission line and shortens the guided wavelength, thereby realizing the miniaturization of microwave–millimeter‐wave antennas and devices. Hideki Hasegawa of Hokkaido University in Japan was among the first scholars to study the SW propagation mode in microstrip lines in 1971 [17, 18]. Subsequently, extensive research on the SW transmission line was conducted in the academic community. The realization methods of the SW microstrip line include bending line [19] (as illustrated in Figure 1.1a) and loading cycle structure [20, 21] (as illustrated in Figure 1.1b and c). The phase velocity of the electromagnetic wave is decreased by increasing the distributed capacitance and inductance of the transmission line. A group from the South China University of Technology, headed by Chu Qingxin, suggested a mixed‐lattice‐based SWS in 2012 [22] (see Figure 1.1d). High SW factor (SWF), minimal insertion loss, and linear phase response over a broad frequency range are benefits of the SW microstrip line.

Figure 1.1 Structure diagram of the slow‐wave microstrip line. (a) Curved line slow‐wave microstrip...

Produkt-Details

• Erscheint lt. Verlag: 23.9.2025
• Sprache: englisch
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Schlagworte: Antenna design • Array Antenna • distributed capacitors • distributed inductors • groove gap waveguide • Horn Antenna • Integrated Antennas • metal waveguides • Microstrip Lines • miniaturized antennas • planar circuits • waveguide couples
• ISBN-10: 1-394-31419-1 / 1394314191
• ISBN-13: 978-1-394-31419-5 / 9781394314195