Antennas and Microwave Engineering MCQs | Page - 4

Explanation: 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.

Explanation: 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.

Explanation: 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.

Explanation: ┌= (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.

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

Explanation: 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.

Explanation: 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.

Explanation: 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.

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

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