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Design of 7 GHz Microstrip Patch Antenna for Satellite IoT (SIoT) and Satellite IoE (SIoE)-Based Smart Agriculture Devices and Precision Farming
Published in Monika Mangla, Ashok Kumar, Vaishali Mehta, Megha Bhushan, Sachi Nandan Mohanty, Real-Life Applications of the Internet of Things, 2022
Manvinder Sharma, Bikramjit Sharma, Anuj Kumar Gupta, Harjinder Singh, Dishant Khosla
The dimensions and shapes vary in various kinds of antenna. There are four subtypes of microstrip antenna which are: MPA, microstrip traveling-wave antenna, printed slot antenna and microstrip dipoles [34]. When the radiation of the wave in a specific direction is similar to the electric field direction then the antenna polarization is determined. A figure is traced at a time through the vector of instantaneous electric field. The antenna can be linearly polarized or circular polarized. The linear polarization has further two subtypes: horizontal polarization and vertical polarization. When the electric field vector and earth are perpendicular to each other, then there is vertical polarization of electromagnetic wave, and when the electric field vector and earth are parallel to each other, then there is horizontal polarization of electromagnetic waves [35].
Multi-Mode Resonant Electric Dipole Antennas
Published in Wen-Jun Lu, Lei Zhu, Multi-Mode Resonant Antennas, 2022
By using fatter dipoles and incorporating linearly tapered structures, the antenna can exhibit a dual-band characteristic, as its symmetric counterpart (Lu et al. 2012) behaves. As illustrated in Figure 2.36a and b, just similar to the symmetric case, relatively flatten input resistance and reactance frequency responses can be attained when α is 80°. When α is too large, the input impedance may fluctuate more drastically, while a too mall α may lead to low input resistance of about 30 Ω. This well validates the residual traveling-wave antenna characteristic incorporated by the linearly tapered configurations (Lu et al. 2012, Schantz 2015). Unlike the symmetric case in (Lu et al. 2012), the input impedance at the low-frequency band is less sensitive to α.
B
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
where f is equal to either J or Y ; is the order of the function and x is its argument. Typically, Bessel functions arise in boundary value problems that are based upon a cylindrical coordinate system. best-fit memory allocation a memory allocator for variable-size segments must search a table of available free spaces to find memory space for a segment. In "best-fit" allocation, the free spaces are linked in increasing size and the search stops at the smallest space of sufficient size. Compare with buddy memory allocation. beta function a measure of beam width. The beta function details how the beam changes around the accelerator. There are separate beta functions for the x and y planes. The square root of bx is proportional to the beam's x-axis extent in phase space. beta particle an electron or positron emitted from a radioactive source. betatron oscillation stable oscillations about the equilibrium orbit in the horizontal and vertical planes. First studied in betatron oscillators, betatron oscillation is the transverse oscillation of particles in a circular accelerator about the equilibrium orbit. The restoring force for the oscillation is provided by focusing components in the magnetic field which act to bend a particle that is off the equilibrium orbit back toward it. Beverage antenna simple traveling wave antenna consisting of an electrically long horizontal wire above ground with a termination resistance between the end of the wire and ground equal to the characteristic impedance of the wire/ground transmission line.
Miniaturized Vivaldi Tapered Slot Antenna (VTSA) with Microstrip to SIW Feed Structure for X Band Application
Published in IETE Journal of Research, 2022
Chanchala Kumari, Neela Chattoraj
Different types of wideband antennas have been investigated in the field of wireless communication. Vivaldi tapered slot antenna (VTSA) with the exponential tapered shape is preferred in many applications, such as medical imaging, radar, wall penetration, etc., due to its simple structure, high gain, constant radiation pattern, easy to fabricate and integration with circuit [1]. It belongs to the tapered slot antennas with an exponential flare profile family. It is one type of traveling wave antenna and it has end-fire radiation. The basic principle of a traveling wave antenna is that the wave travels along with the antenna structure with a phase velocity (Vph) < velocity of light (c) in free space. When the separation between the conductors is very small compared to a free space wavelength traveling wave’s energy is firmly attached to the conductor, and the waves weaken and become more related to the radiation field as the spacing widens. This type of antenna is slow wave with a wide impedance bandwidth. The performance of VTSA mainly depends upon the flare structure that is gradually tapered. The higher frequency component radiates close to the antenna’s narrower portion, and at the broader part, the lower frequency component emits. The antenna’s performance (such as beam width, side lobes level, back lobes levels, and antenna bandwidth) mainly depends on the flare structure, feeding structure, size, and shape. As the flare structures are designed on the opposite side of the substrate it is called antipodal Vivaldi antenna [2]. The upper metal shapes of the substrate act as a conductor and the bottom metal parts of the structure act as a ground plane. Both the shapes are flare and the mirror image of each other. In the case of the bipodal Vivaldi antenna, the two flare shapes of the same structure are designed on the same layer of the substrate, but in the case of the antipodal Vivaldi antenna slot line, half flare metal portion is etched on the substrate’s two sides [3,4]. With this configuration, the feed line to slot line transition is removed, and the Vivaldi antenna’s impedance bandwidth is increased.