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Prospects of MMIC Antennas
Published in Devendra Kumar Sharma, Rohit Sharma, Bhadra Pokharel, Vinod Kumar, Raghvendra Kumar, Advances in Antenna, Signal Processing, and Microelectronics Engineering, 2021
Satya Sai Srikant, Saptarshi Gupta, Atul Kumar Pandey
It is an important characterization parameter that is mostly considered in practical antenna applications to optimize. For aperture efficiency, such types of applications are used to characterize for the offset feed reflector, Cassegrain reflector, and prime focus reflector, which desire the feed antenna along with the reflector. Such types of systems are commonly used for base station microwave links for mobile communication, satellite communication, and radio astronomy. Henceforth, one can say that aperture efficiency in the reflector antenna framework does not only depend on feed antenna radiation patterns but also depends on the term f/D, where f and D are shown in Figure 5.2. Also, the optimization of the aperture efficiency for reflector antennas occurs for the uniform distribution of the E-field over an aperture, and it comes with trade-offs. An ideal radiator is required for the uniform distribution of the E-field over an aperture to ensure that a balanced amplitude of the E-field radiate in every direction. In any case, for all intents and purposes, this type of isotropic antenna is impossible, and therefore the feed pattern with finite directivity, that is, the tapered E-field distribution over an aperture is preferable. It reflects well-known overflow and light efficiency trade-offs, which are shown in Figure 5.2.
Aperture and Phased Array Antennas
Published in Habibur Rahman, Fundamental Principles of Radar, 2019
The basic operation of Cassegrain reflector antenna may be described by means of a schematic diagram in Figure 11.3. It consists of a feed horn, a subreflector, and a main reflector. The subreflector is situated between the focal point and the vertex of the main reflector with one of its foci coincident with the focus of the main reflector. The feeding horn is situated at the other focus of the subreflector, which also determines the overall focal length of the system. The subreflector is assumed to be in the far field of the feed system. Spherical waves emanating from the feeding system are transformed after a reflection by the subreflector into a second set of spherical waves. These appear to emanate from a virtual focus on the paraboloid reflector, which transforms them into plane wave propagating in the axial direction.
Satellite Antennas
Published in Jerry D. Gibson, The Communications Handbook, 2018
Yeongming Hwang, Youn Ho Choung
A reflector antenna system consists of one or more reflector surfaces. The surface can be solid, gridded, printed substrate, or meshed. It may be paraboloid, hyperboloid, spheroid, ellipsoid, or general in shape. Seven antenna types that have been most commonly used for satellite communication systems are summarized in Table 65.3. They include the parabolic reflector and the Cassegrain reflector, both either center fed or offset fed, the overlapped dual-gridded reflector, a multireflector system with a frequency selective surface (FSS) subreflector, and the deployable reflector antenna.
A Brief Review on mm-Wave Antennas for 5G and Beyond Applications
Published in IETE Technical Review, 2023
Paikhomba Loktongbam, Debasish Pal, A. K. Bandyopadhyay, Chaitali Koley
In the mm-wave frequency band, the antenna's gain is limited by its small size. As we go up in frequency, the problem becomes more and more severe. A natural choice for a high gain antenna in the THz regime is reflector antennas like reflector array [62–64], Gregorian reflector [65], Cassegrain reflector [66], etc. But these antennas have their own disadvantages, like bulky nature, difficult to fabricate, incompatibility with on-chip applications, high cost, etc. Although printed antennas overcome many of these disadvantages, they too have some drawbacks. Printed antennas often underperform due to their high substrate loss, low metal conductivity, rough surface finish in antenna surface, etc. [67]. Another approach to increase the gain of the mm-wave antenna is to adopt the Fabri-Parrot cavity approach [68]. This approach usually provides high directivity, but the challenges in designing these high gain antennas are low radiation efficiency and narrow bandwidth.
UWB full polarization single-plane monopulse reflector antenna
Published in Electromagnetics, 2023
Antenna radiator elements may be spaced closer if they are loaded by dielectric materials. Miniaturized antennas are a good candidate for monopulse array (Shafai 2005; Shi, Amert, and Whites 2015). Jargalsaikan and Bang (2019) used five dielectric rod antenna for monopulse Cassegrain reflector. Bandwidth of 18% (13.9–16.7 GHz) is reported for this architecture. A dual band monopulse satellite tracking antenna consisting of dielectric rod array is proposed (Kumar, Kumar, and Srinivasan 2013). Four elements in 2 × 2 array configuration are operated for downlink (3.4–4.2 GHz) reception and tracking applications. One single element with high gain at the center of the array operates for uplink (6.3–6.8 GHz)