Total antenna efficiency

The total antenna efficiency quantifies that fraction of the maximum power available at the generator that is radiated by the antenna in the smrounding space. The total power... 

Anantha, V. and Taflove, A. (2002). Efficient modeling of infinite scatterers using a generalized total-field/scattered-field FDTD boundary partially embedded within PML leee Transactions on Antennas and Propagation 50 1337-1349. 

Table 2 shows the result of quantitative measurements of P700 and QA in isolated thylakoid membranes. Control C. reinhardtii exhibited a P700/Chl ratio of 2.14/1 (mmol/mol) and a QA/Chl ratio of 1.96/1. Relative to total Chi, the Chi Mess mutant had a greater content in P700 and QA (P700/Chl=3.1/1 and QA/Chl=2.95/1). This is consistent with a depletion of Chi from the Chi antenna of this mutant. The ratio of QA/P700 provided an estimate of PSU/PSI ratio in the thylakoid membrane of the two strains. This ratio was 0.92 1 for the control and 0.95 1 for Chi Mess (Table 2). The efficiency of PSII primary photochemistry was also estimated from the in vivo variable to maximal Chi fluorescence (Fv/Fmax) yield ratio [Kitajima and Butler 1975]. This ratio was 0.65 for the control and 0.52 for the Chi Mess mutant.

Efficiency to maximize the radiated power, the antenna designer wiU aim at a large radiation efficiency. As previously discussed, the total efficiency is the product of two terms. The first one, the impedance mismatch factor M, can he maximized by minimizing the reflection coefficient. The second term, the conductive-dielectric efficiency Ced can be maximized by using textile materials with low ohmic and dielectric losses, ie, electrotextiles with high conductivity and textile dielectric substrates with low tan 6. 

The DSCS-III satellite offers six covert communications channels and is equipped with spatial user-jammer discrimination capability, which sometimes is known as antenna nulling capability, to achieve high discrimination performance. According to the published literature, two channels in this satellite system deploy high-efficiency 40 W TWTAs and the remaining four channels each use only 10 W TWTAs. This means that the total RF output of the TWTAs is 120 W. Assuming a DC-to-RF efficiency of 40% each, the DC input power required for the TWTAs will be close to 300 W. The batteries must supply this amount of DC power. In addition, additional DC power is required to operate the antenna stabilization mechanisms and the various electronics, electro-optic, and microwave sensors onboard the satellite. The solar panels must be capable of charging the batteries to meet all the DC power consumption. 

The measured total efficiency of the standalone stretchable patch antenna including mismatch losses is 36.9% in its relaxed state at 1.46 GHz. Straining the patch to 15% along its x-axis leads to significant total efficiency decrease of 33.8%. In the intermediate states with the strains between 5% and 10%, the total efficiency of 11.5% and 5.8% is achieved according to the experiments. 

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