Antennas and Microwave Engineering MCQs | Page - 4

 in the g/t ratio of an antenna, g is the gain of an antenna and t is the antenna noise temperature. higher the g/t ratio of an antenna better is the performance of the antenna.

 thermal noise has a power spectral density for a wide range of frequencies. its plot of frequency v/s noise power is a straight line parallel to y axis.

 slotted line allows the sampling of the electric field amplitude of a standing wave on a terminated line. with this device, swr and the distance of the first voltage minimum from the load can be measured, from this data, load impedance can be found.

 ┌= (swr-1)/ (swr+1). substituting for swr in the above equation for reflection co-efficient, given swr is 1.4, reflection co-efficient is 0.16667.

 swr= (1+┌)/ (1-┌). where ┌ is the reflection co-efficient. substituting for the reflection co-efficient in the equation, swr is 2.3333.

 lmin is defined as the distance between the terminating load of a transmission line and the first voltage minimum that occurs in the transmission line due to reflection of waves from the load end due to mismatched termination.

 zl=z0 (1+┌)/ (1-┌), this is the expression for load impedance. normalized load impedance is the ratio of load impedance to the characteristic impedance, taking zll/z0 as 2, the reflection co-efficient is equal to 0.33334.

 the link analysis and its output, the link budget consists of calculations and tabulations of useful signal power and interfering noise power at the receiver.

 there are two primary causes for the degradation of error performance.

 when a local oscillator is used in signal mixing, phase fluctuations and jitter adds phase noise to the signal.