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CRLH Metamaterial Antennas, Part II: Leaky-Wave and Resonant Antennas
Published in Filippo Capolino, Applications of Metamaterials, 2017
A leaky-wave antenna is an antenna whose radiation is produced by a traveling wave progressively leaking out power as it propagates along the antenna structure, which operates as a leaky waveguide [6]. If the direction of propagation is x and the direction perpendicular to the plane of the antenna radiator is z, as illustrated in Figure 16.1a, the wave in free space above the antenna has the form
Antennas or aerials
Published in Geoff Lewis, Communications Technology Handbook, 2013
Leaky feeder/leaky wave antenna. A length of waveguide with a longitudinal slot or row of holes, or co-axial cable with purposely poor shielding, can lose energy continuously along its length. This provides an effective way of transmitting signals within a tunnel or underground system. These are often described as fast or guided wave structures.
A liquid crystal leaky-wave antenna with fixed-frequency beam scanning and open-stop-band suppression
Published in Liquid Crystals, 2022
Shanzhe Wang, Zheng Li, Xiaoxi Chen, Meie Chen, Junhong Wang
The leaky-wave antenna (LWA) is a pre-eminent candidate with respect to modern communication systems since it is easy for low-cost fabrication and can readily realise high-directivity beam without complex feeding [1]. In particular, the LWA has good properties for beam scanning by controlling the frequency variation [2]. It is noted that open stop-band (OSB) defects usually occur in conventional LWAs, deteriorating their performance in broadside radiation. In order to avoid the impact of the OSB, quite a lot of methods have been reported [3,4], and hence a continuous beam scanning from backwards to forwards including broadside could be realised in these LWAs, which is beneficial for applications, such as satcom and mobile communication systems. For a conventional periodic LWA with a period length P, an effective technology to eliminate the OSB is to adopt an extra radiated array, which has a distance of a quarter of P to reduce the reflection-superposition influence, as presented in [5]. Nevertheless, the extra array might cause other effects such as high side lobe levels and strong mutual couplings between elements. Therefore, in this work, a modified way by introducing an offset rather than an extra array is employed, which will be explained in detail in the following pages.
Magnetically scannable slotted waveguide antenna based on the ferrite with gain enhancement
Published in Waves in Random and Complex Media, 2021
Morteza Mohammadi Shirkolaei, Javad Ghalibafan
The leaky-wave antenna (LWA) is a traveling wave structure which is increasingly used in radar and scanning applications due to having low-profile and simple fabrication [1–6]. Continuous beam scanning is desirable which functions as the important specification in the LWA [7–13]. The direction of the main lobe in the LWA is a function of the propagation constant of β [14]. Since the CRLH metamaterial can provide both the negative and positive values for the propagation constant [15–20], then the CRLH structure should be used as a proper option to reach scanning from the negative angles to the positive ones [21–24].
Photonic waveguide inspired corrugated cross-coupled notch DRA
Published in Electromagnetics, 2018
Duggirala Venkata Kiran, Dileep Sankara Narayanan, Vinay Kumar Killamsetty, Biswajeet Mukherjee
The series of corrugated slot is applied to the top surface of the basic RDRA which is shown in Figure 4a and is called as Corrugated DRA (CDRA). The most attractive features of such corrugated structure is that it acts as a leaky wave antenna with enhanced gain but at the cost of impedance mismatch.