Antenna

Consider the Friis' transmission equation $P_R = (P_T G_T G_R \lambda^2)/(4\pi D)^2$, where $P_R$ and $P_T$ are the received and the transmitted powers, respectively. $G_T$ and $G_...

An antenna with a directive gain of 6 dB is radiating a total power of 16 kw . The amplitude of the electric field in free space at a distance of 8 km from the antenna in the direc...

A half wavelength dipole is kept in the x-y plane and oriented along $${45^ \circ }$$ from the x-axis. Determine the direction of null in the radiation pattern for $$0 \le \phi \le...

An antenna pointing in a certain direction has a noise temperature of $$50K$$. The ambient temperature is $$290K$$. The antenna is connected to a pre-amplifier that has a noise fig...

The electric field of a uniform plane wave travelling along the negative $$z$$ direction is given by the following equation: $$$\overrightarrow E {}_w^i = \left( {{{\widehat a}_{_x...

The far-zone power density radiated by a helical antenna is approximated as: $$$\overrightarrow W {\,_{rad}} = \overrightarrow W \,average\, \approx \,\widehat a{}_rC{}_0\,{1 \over...

The radiation pattern of an antenna in spherical co-ordinates is given by $$$F\,(\theta )\, = {\cos ^4}\,\theta \,\,\,;\,\,0\,\, \le \,\,\theta \,\, \le \,\,\pi /2$$$ The directivi...

A transmission line is feeding 1 Watt of power to a horn antenna having gain of 10 dB. The antenna is matched to the transmission line. The total power radiated by the horn antenna...

Consider a lossless antenna with a directive gain of + 6 dB. If 1 m W of power is fed to it the total power radiated by the antenna will be

For an 8 feet (2.4 m) parabolic disk antenna operating at 4 GHz, the minimum distance required for far field measurement is closest to

The half-power beam widths (HPBW) of an antenna in the two orthogonal planes are $${100^ \circ }$$ and $${60^ \circ }$$ respectively. The directivity of the antenna is approximatel...

The average power of an omni-directional antenna varies as the magnitude of cos($$\theta $$) where $$\theta $$ is the azimuthal angle. Calculate the maximum Directive Gain of the a...

A transmitting antenna radiates 251 W isotropically. A receiving antenna, located 100m away from the transmitting antenna, has an effective aperture of 500 cm 2 . The total power r...

An antenna in free space receives 2$$\mu $$ W of power when the incident electric field is 20 m V/m rms. The effective aperture of the antenna is

The vector $$\mathop H\limits^ \to $$ in the far field of an antenna satisfiels

The far field of an antenna varies with distance r as

A parabolic dish antenna has a conical beam 2 0 wide. The directivity of the antenna is approximately

An antenna when radiating, has a highly directional radiation pattern. When the antenna is receiving its radiation pattern

In the case of ground wave propagation, at far-off distances from the transmitting tower antenna, the Poynting vector is