Antenna gain

We run Monte Carlo simulations to examine the performance of the sensor selection algorithm based on the maximization of mutual information for the distributed data fusion architecture. We examine two scenarios first is the sparser one, which consists of 50 sensors which are randomly deployed in the 200 m x 200 m area. The second is a denser scenario in which 100 sensors are deployed in the same area. All data points in the graphs represent the means of ten runs. A target moves in the area according to the process model described in Section 4. We utilize the Neyman-Pearson detector [20, 30] with a = 0.05, L = 100, r) = 2, 2-dB antenna gain, -30-dB sensor transmission power and -6-dB noise power. 

Figure 1. Transmitted power versus transmitted pulse length for X-band radar (30 dB antenna gain) — detection of ldBsm (1 square meter) target at distance 50 km.

To increase the detection range one can increase the transmitted power, antenna gain or integration time. 

Optical communication may give the design power efficiency that we would not otherwise be able to obtain. Optical transmission provides extremely high antenna gain and the received power only decays as the inverse of the distance squared [War 01, War 05], Optical systems can be made extremely tiny. Finally, it is very difficult to eavesdrop on collimated optical communication, which is a significant advantage for security and defense applications [War 05],... 

High antenna gain means that microwave transmitters need not be extremely powerful to produce a strong... 

As a consequence, different types of terminal will receive different power values because different terminals have different antenna gains. Another issue found in these systems is related with the attenuation due to obstacles. The PL term in (13.4) is dependent both on the free space losses and the attenuation due to obstacles between the transmitting and the receiving antennas. This means that for the same terminal different RSS values for the same references can be obtained at the same point, e.g. a cell phone will have different RSS values when placed on a table or when it is inside a pocket. 

Fig. 2.4 The power Free received by the antenna will be reradiated as Prati = P c I r - In the bistatic direction Sr the antenna gain is Gr and we obtain a power density Or = Prsfi/4jtr GrPn where Pr is the polarization mismatch between the antenna and a receiving antenna.

We opened this chapter with a review of the classical theory of antenna scattering. The total RCS of any antenna could be written as the phasor addition of two components, namely the antenna and the residual mode components. The first of these was clearly and precisely defined by the antenna gain G, the reflection... 

TABLE 13.7 Various Combinations of Transmitter Power and Antenna Gain that will Produce 100-kW ERP for an FM Station... 

The ideal combination of antenna gain and transmitter power for a particular installation involves the analysis of a number of parameters. As shown in Table 13.7, a variety of pairings can be made to achieve the same ERP. 

TABLE 16.4 Power and Antenna Gain Combinations to Achieve... 

Transmitter Power, kW No. Bays Antenna Gain, dB Feedline Efficiency, % EflFective Radiated Power, kW... 

Maximum power output Hmits are specified by the FCC for each type of service. The maximum effective radiated power (ERP) for low-band VHF is 100 kW, for high-band VHF it is 316 kW, and for UHF it is 5 MW. The ERP of a station is a function of transmitter power output (TPO) and antenna gain. ERP is determined by multiplying these two quantities together, and subtracting transmission line loss. 

At first examination, it might seem reasonable and economical to achieve licensed ERP using the lowest transmitter power output possible and highest antenna gain. Other factors, however, come into play that make the most obvious solution not always the best solution. Factors that limit the use of high-gain antennas include... 

Boltzmann s constant, 10 log(fc) = —228.6 dBW/K/Hz, T is the system noise temperature in kelvins and B = 10 log(bandwidth (Hz)) is the bandwidth in decibel hertz. Then, (G — 10 log T) dB/K is a figure of merit for the satellite or Earth receiving system. It is usually written as G/T and read as gee over tee. The antenna gain and the noise temperature must be defined at the same reference point, for example, at... 

Antenna gain-to-noise temperature For a satellite earth terminal receiving system, a hgure of merit that equals G/T, where Gis the gain in dB of the earth terminal antenna at the receive frequency, and T is the equivalent noise temperature of the receiving system in Kelvins. 

Antenna gain is defined the signal level ratio against the objected direction to total power from antenna. So, horizontal and vertical omni-directivity antenna gain is 0 dBi. 

Vertical dipole antenna is shown as figure 1 and its horizontal is omni-directivity, but vertical is not, so the antenna gain is 2.16 dBi. 

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