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Multiband MIMO antennas
Published in Yadwinder Kumar, Shrivishal Tripathi, Balwinder Raj, Multifunctional MIMO Antennas, 2022
Harsh Verdhan Singh, D. Venkata Siva Prasad, Shrivishal Tripathi
Monopole antennas utilize a λ/4 length structure to resonate if the electrical field at the input is a minimum and the current is a maximum. An analogous circumstance occurs at the feed when the element size is 3λ/4. Thus, for a fixed antenna dimension, the feed circumstances will be equivalent when the frequency is comparable to heights of λ/4 and 3λ/4: the monopole will be resonant at an initial frequency and at a frequency three times higher than the initial frequency, as shown in Figure 5.1. Additional sophisticated resonances exist at higher frequencies. This technique is used in numerous types of resonant antennas such as dipoles, patches, slots, dielectric resonators, and monopoles and is repeatedly utilized (and controlled) to achieve multiband behavior [14].
Basic Antenna Parameters and Definitions
Published in Victor Rabinovich, Nikolai Alexandrov, Basim Alkhateeb, Automotive Antenna Design and Applications, 2010
Victor Rabinovich, Nikolai Alexandrov, Basim Alkhateeb
A simple monopole antenna mounted on an infinite metal screen has only an omnidirectional radiation pattern Fθ (θ, φ) that does not depend on the φ angle value (Fφ (θ, φ) = 0). A whip antenna mounted on a fender has components Fθ (θ, φ) and Fφ (θ, φ) in horizontal and vertical planes due to the effects of car body shadow. Both components in horizontal plane (θ = 90 degrees) are not omnidirectional. The important parameter γ that equals the maximum-to-minimum ratio of the radiation pattern value in horizontal plane when measuring 360 degrees around a car determines the quality of the whip antenna design. Whip antennas usually meet the requirement when γ is less than 12 to 15 dB for the Fθ (θ = 90°, φ) component. Antennas printed on window glass suffer from more dip variations of directionality over a 360 degree span (sometimes more than 25 dB). However, these dips are generally very narrow and do not exceed a few degrees. As a rule, radiation pattern levels are relative values with respect to certain reference values and expressed in decibels.
M
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
monopole antenna an antenna consisting of a straight conducting rod, wire, or other structure oriented perpendicularly to a ground plane and fed at the junction of the structure and the ground plane. monostatic scattering the reflection of a portion of an electromagnetic wave back in the direction of the wave source. Monostatic scattering is measured by having the transmitter and receiver collocated. Monte Carlo method a numerical technique that replaces a deterministic description of a problem with a set of random descriptions that have been chosen based on distributions that match the underlying physical description of the problem. This technique is widely used to investigate transport and terminal characteristics in small semiconductor structures.
Metamaterial Loaded Antenna with Improved Efficiency and Gain for Wideband Application
Published in IETE Journal of Research, 2023
KM Neeshu, Anjini Kumar Tiwary
Radiation pattern of the proposed antenna is analyzed at the frequencies 4, 8, and 12 GHz. It is observed in Figure 7(a) that the radiation pattern is omnidirectional similar to that of monopole antenna, at 4 GHz. The radiation pattern at 8 GHz and 12 GHz are presented in Figure 7(b,c), respectively. It is observed that the maximum radiation is in the opposite direction of antenna ground plane. The radiation pattern changes from omnidirectional to directional due to the ground plane [15] which acts as a reflector for higher frequencies. At 3 GHz, the ground plane size of around 8 mm (λ/10) is too small to serve as a reflector, whereas for higher frequencies 8 GHz (λ/5) and 12 GHz (λ/3), the ground plane gives significant impact to act as a reflector. Figure 8 illustrates the simulated and measured radiation pattern of the antenna, including the co-polarization and cross-polarization in the xz and yz planes. It shows nearly omnidirectional pattern in the xz plane, whereas directional pattern in the yz plane. The antenna has large cross-polarized power level in the plane due to the asymmetrical feed line. There is some discrepancy between the measured and simulation results due to testing environment and manufacturing constraints.
A circularly polarised monopole antenna with switchable frequency, pattern and polarisation
Published in International Journal of Electronics, 2022
Ankit Bhattacharjee, Santanu Dwari
On the other hand, from the application point of view, monopole antenna has been a good choice because of its various advantages like simplicity in design, easy understandable mechanism, straightforward way of achieving narrow band, multiband and also wide band performances, easy implementation on planar form, compact in size etc. So, reconfigurable techniques have also been applied to different monopole configurations to modify various antenna parameters electronically in (Bhattacharjee et al., 2019; Boudaghi et al., 2012; Cao et al., 2015; Juan et al., 2017; Liang et al., 2015; Raman et al., 2013; Shi et al., 2012; A. Singh et al., 2019). Frequency reconfiguration is achieved with the help of a circular monopole antenna with PIN diode based switchable slotted ground plane in Boudaghi et al. (2012) and a monopole with water filled substrate milled channels in A. Singh et al. (2019). Switchable parasitic elements based designs are introduced in Juan et al. 2017) and Shi et al. (2012) for controlling the radiation beam from a driven monopole. Reconfigurable operation for circular polarisations are done in Bhattacharjee et al. (2019) and Cao et al. (2015) with the simple ring monopole and meandered monopole respectively. However, all the reported works in Bhattacharjee et al. (2019); Boudaghi et al. (2012); Cao et al. (2015); Juan et al. (2017); Shi et al. (2012); A. Singh et al. (2019) are based on single parameter reconfiguration, reconfigurable mechanism is complex in A. Singh et al. (2019) and Cao et al. (2015), and configurations are not planar in Juan et al. (2017) and Shi et al. (2012).
Design and Fabrication of a Low-Cost Mobile Antenna for Low VHF
Published in IETE Journal of Research, 2021
Mahmood Rafaei-Booket, Sina Hasibi-Taheri
Since the omni-directional mobile antenna in a low VHF band can be used in heavy trucked as well as lighter wheeled military vehicles, the low-weight, low visibility structures with a simple design and wideband capabilities are most required for portable wireless communication. Meanwhile, wire dipole and monopole antennas are popular candidates due to their simple configurations, linear polarization, and omni-directional radiation patterns [1–3]. The main drawback of wire dipole/monopole antennas is their narrow bandwidth. So far, various loading techniques have been reported in the literature for their impedance bandwidth increasing [4–7]. However, such loading approaches lead to designing complicated implementations or require active circuits. In addition, a monopole antenna needs a ground plane practically, which is not suitable in mobile applications.