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Design and Measurements Process of Wearable Communication, Medical and IOT Systems
Published in Albert Sabban, Wearable Systems and Antennas Technologies for 5G, IOT and Medical Systems, 2020
Radiation efficiency is the ratio of power radiated to the total input power, α = G/D. The efficiency of an antenna takes into account losses and is equal to the total radiated power divided by the radiated power of an ideal lossless antenna. Efficiency is equal to the radiation resistance divided by total resistance (real part) of the feed-point impedance. Efficiency is defined as the ratio of the power that is radiated to the total power used by the antenna as given in Equation 17.24. Total power is equal to power radiated plus power loss. α=PrPr+Pl
Electromagnetic Fields
Published in Christos Christopoulos, Principles and Techniques of Electromagnetic Compatibility, 2022
This radiation pattern is shown in Figure 2.14. The directivity of an antenna is equal to the maximum value of its directive gain. Hence, the directivity of the dipole considered here is equal to 1.5. The gain G of an antenna is equal to its directive gain times its radiation efficiency. In most cases, radiation efficiency is very high and the gain is approximately equal to the directivity. In many applications the gain is expressed in decibels: G(dB)=10 logG
Design and Developments of UWB Antennas
Published in Chinmoy Saha, Jawad Y. Siddiqui, Yahia M.M. Antar, Multifunctional Ultrawideband Antennas, 2019
Chinmoy Saha, Jawad Y. Siddiqui, Yahia M.M. Antar
Radiation efficiency of an antenna is defined as the ratio of the total power radiated (Prad) by an antenna to the power coupled to the antenna (Pin) through a transmission line. Thus, radiation efficiency, ηrad=PradPin
Implementation of the Metamaterial Multiband Frequency Reconfigurable Antenna for IoT Wireless Standards
Published in IETE Journal of Research, 2023
Ritesh Kumar Saraswat, Mithilesh Kumar
The experimental radiation efficiency of the antenna is obtained by using an anechoic chamber, where a small amount of power is fed to the antenna with the help of the feed pads and measure the strength of the radiated electromagnetic field in the surrounding space. The proposed design radiates the 22–83% of the energy fed to it (−3 to −2.2 dB) (efficiency = total emitted energy/supply energy). According to the IEEE standards, radiation efficiency is defined as “the ratio of the total power radiated by an antenna to the net power accepted by the antenna from the connected transmitter”. Due to the reflectivity (mismatch) at the antenna, the net power decreases from the forward power from a major portion of the energy back to the source. Antenna gain is directivity plus (total) efficiency in dB. The measured radiation efficiency is attained in an anechoic chamber with the help of a vector network analyzer (VNA). A power meter is also connected with this arrangement to measure the power supplied to the antenna and the E field at the selected sampling points. A calibrated field probe or antenna is required for the E field measurement as well. A VNA is needed to measure the reflection coefficient of the antenna.
Triple Band Microstrip Patch Antenna Useful for Wi-Fi and WiMAX
Published in IETE Journal of Research, 2022
Simulated and measured gain and radiation efficiency curve of the proposed antenna is shown in Figure 9. The proposed antenna has a peak gain of 3.0209 dB. It is very small in the lower frequency band because of very small size. It has a gain of 2.17 dB in the middle frequency band. The proposed antenna’s peak radiation efficiency is 75.9351% and radiation efficiency is maintained above 40% in the entire operating range (2.34–2.46, 4.61–5.92 and 9–9.9 GHz). After observing both graphs, i.e. gain and radiation efficiency, we can see that gain of the designed antenna is lower in the low-frequency band (frequency <2.5 GHz) than in the high-frequency band (frequency >7 GHz), but the radiation efficiency is higher in the low-frequency band than the one in the high-frequency band and they both are approximately same in the middle frequency band, i.e. 2.5–7 GHz. This can be explained by viewing the directional properties of the antenna. At higher frequencies, directional properties of the antenna are increased because of larger electrical size giving rise to high gain, but it starts decreasing in the low-frequency range due to higher order modes. But radiation efficiency mainly depends on losses and normally the dielectric loss is increased with frequency; therefore, there is a gradual decrease in radiation efficiency of the antenna. Also, when the gain of the antenna decreases, radiation efficiency of the antenna also decreases.
CSRR-Loaded Compact Quad Port MIMO Diversity Antenna for UWB Applications
Published in IETE Journal of Research, 2021
Pankaj Kumar Keshri, Sanjay Kumar Sahu, Richa Chandel
Initially, the measured peak gain increases monotonically to a maximum of 3.6 dB at 8.8 GHz and then decreases to a minimum of 0.5 dB. It is replicated further to have a maximum of 3.6 dB at 15.4 GHz through the entire operating UWB range, as presented in Figure 14. The total radiation efficiency of MIMO antenna from port n, where denotes the decoupling efficiency as given by M = no. of ports in the MIMO antenna; represents the radiation efficiency of the radiating mode at port n. The radiation efficiency of the antenna varied from 50% to 84%. Simulated and measured results are parallel.