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Basic Theory and Design of Printed Antennas
Published in Binod Kumar Kanaujia, Surendra Kumar Gupta, Jugul Kishor, Deepak Gangwar, Printed Antennas, 2020
Shilpee Patil, Binod Kumar Kanaujia, Anil Kumar Singh
The antenna gain is a key performance value which is measured in terms of the antenna’s directivity and radiation efficiency. As the radiation efficiency never reaches the maximum, the gain of an antenna always has lower values than the directivity. Antenna efficiency is another important parameter which is most often used to measure losses in antennas and is defined as the ratio of the radiated power to the input power of the antenna. The input power is transformed into the radiated power, and it is mostly dissipated within the antenna by means of metal conduction, magnetic loss and dielectric loss. Surface wave power is also a transformed portion of the input power of the antenna. At the boundaries of the substrate, surface waves that travel within the substrate are partially radiated and reflected back. Surface waves are mostly generated when a thick substrate or a substrate with a large dielectric constant is used. When air is used as a dielectric, surface waves are not excited. Presently, various techniques are available to minimize the excitation of surface waves.
Basic Antennas for Wearable Communication Systems
Published in Albert Sabban, Novel Wearable Antennas for Communication and Medical Systems, 2017
For small antennas or for antennas without losses, D = G, losses are negligible. For a given θ and φ for small antennas the approximate directivity is given by Equation 4.23. D=41,253θ3dBϕ3dBG=ξDξ=Efficiency Antenna losses degrade the antenna efficiency. They consist of conductor loss, dielectric loss, radiation loss, and mismatch losses. For resonant small antennas, ξ = 1. For reflector and horn antennas the efficiency varies from ξ = 0.5 to ξ = 0.7. The beam width of a small dipole, 0.1 λ long, is around 90°. The 0.1 λ dipole impedance is around 2 Ω. The beam width of a dipole 0.5 λ long is around 80°. The impedance of a 0.5 λ dipole is around 73 Ω.
Antennas for Wearable 5G Communication and Medical Systems
Published in Albert Sabban, Wearable Systems and Antennas Technologies for 5G, IOT and Medical Systems, 2020
Antenna losses degrade the antenna efficiency. Antenna losses consist of conductor loss, dielectric loss, radiation loss and mismatch losses. For resonant small antennas ξ = 1. For reflector and horn antennas, the efficiency varies between ξ = 0.5 and ξ = 0.7. The beam width of a small dipole, 0.1 λ long, is around 90°. The 0.1 λ dipole impedance is around 2 Ω. The beam width of a dipole, 0.5 λ long, is around 80°. The impedance of a 0.5 λ dipole is around 73 Ω.
Metamaterial Loaded Antenna with Improved Efficiency and Gain for Wideband Application
Published in IETE Journal of Research, 2023
KM Neeshu, Anjini Kumar Tiwary
The gain and radiation efficiency are presented in Figure 6. In the operating band, simulation gain varies in the range of 3.30–7.2 dBi and it shows a peak value of 7.89 dBi at 13.3 GHz. Gain of the antenna can be improved by using epsilon very large (EVL) material [14]. In this work, TSCCR and SSDCS both unit cells give high value of real εr keeping imaginary εr low which yields low loss and improved gain. In addition to this, effective area of the proposed antenna also increases with a higher frequency. Thus, the gain increases from 1.5 dBi to around 7.2 dBi for the frequency range 2.88–14 GHz. The radiation efficiency of antenna depends on impedance matching and with unit cell loading better impedance matching is achieved for wider frequency band. The wideband response of antenna shows a low-quality factor (Q) which results reduced surface waves. Thus, the proposed antenna maintains better antenna efficiency by suppressing impedance mismatch loss and surface wave. The SSDCS has higher imaginary permittivity for higher frequency which causes drop in antenna efficiency after 8 GHz. To compensate this drop, partial unit cell has been removed from the bottom layer and it has minimum impact on lower frequencies. As a result of this in ultra-wideband, the radiation efficiency achieved is almost more than 75%.
Dingo Optimizer Plus Black Widow Optimization-Based Optimal Design of Multiband U-Slot Microstrip Patch Antenna
Published in Cybernetics and Systems, 2023
This sub-division explains the performances of varied metrics such as efficiency, gain, VSWR, return losses, and reflection coefficient for varied frequencies. This analysis is done by setting up the frequency from 1, 1.25, 1.5, 1.75, 2, and 2.4 GHz. “Antenna Efficiency is the ratio of power radiated by the antenna to the power supplied to the antenna.” Therefore, the antenna’s efficiency should be high for better design of the U-slot antenna. From Table 2, the efficiency decreases with increasing frequency. However, at 2.4 GHz, a high-efficiency value (0.972) is attained by the developed model. Nevertheless, the introduced scheme shows a high efficiency of 0.98 that is higher than all the other attained outcomes. “Gain is defined as the ratio of the radiation intensity, in a given direction, to the radiation intensity that would be obtained if the power accepted by the antenna were radiated isotropically.” As a result, the gain should be higher to accomplish a superior antenna model. While analyzing Table 3, the gain decreases with an increase in frequency. Predominantly, when the frequency is 1 GHz, the suggested BWDM-LCM method has accomplished a higher gain of 1.68.
Compact Configured 5G Dual-Band MIMO Loop Antenna System
Published in IETE Journal of Research, 2021
Shu-Chuan Chen, Sheng-Min Li, Bo-Xun Lai
Figure 8 shows the measured antenna efficiency of a dual-band MIMO 5G eight antennas. The measured antenna efficiency in the low-band is 35%–58% and 45%–62% for the high-band, both of which are better than 35%. Figure 9 shows at 3430 and 4880 MHz the three-dimensional far-field radiation patterns when only one of the eight antennas is excited and the other seven are terminated in a 50-ohm load. The 3430 and 4880 MHz are the resonant frequencies for low- and high- band. It can be seen that the patterns of the first set of four antennas and the second set of four antennas show a certain degree of left-right symmetry, which is related to the reflection configuration of the two sets thereof, and the far-field radiation patterns of the other eight antennas are less similar. This is why the ECCs calculated from the measured complex E-field radiation patterns are smaller than 0.2 in Figure 7. This means that the antenna system is very suitable for MIMO system operation.