What are the measurements of the antenna?

What are the measurements of the antenna?

Typical parameters of antennas are gain, bandwidth, radiation pattern, beamwidth, polarization, and impedance. The antenna pattern is the response of the antenna to a plane wave incident from a given direction or the relative power density of the wave transmitted by the antenna in a given direction.

Where do we measure the radiation pattern of an antenna?

The radiation pattern is a graphical representation of the distribution of radiation energy as a function of angle about the antenna in the three-dimensional space and is generally measured in the far field region.

How radiation pattern of an antenna can be measured experimentally?

The test antenna is rotated using the test antenna’s positioning system. The received power is recorded at each position. In this manner, the magnitude of the radiation pattern of the test antenna can be determined.

What is radiation intensity of antenna?

Radiation intensity, or the antenna power pattern, in a given direction is defined as the power radiated from an antenna per unit solid angle. The radiation intensity is a far field parameter which can be obtained by simply multiplying the radiation power density by the square distance, i.e., (2.99)

How is antenna current measured?

Antenna current is commonly measured in MW/SW high power transmitters, it’s mostly done to monitor output power or as an input to automatic antenna tuner. Nowadays a simple current transformer is invariably used while in the early radio era this was often a hot wire ammeter.

How is antenna power measured?

Antenna efficiency is expressed either in percentage or dB. Total Radiated Power is measured on an antenna test range, most often an anechoic chamber. The transmitter is excited in some fashion, outputting power to the antenna. The antenna then radiates this power.

How is antenna bandwidth calculated?

Bandwidth for antenna can be calculated taking reference level of VSWR=2, or reflection coefficient =-10dB or return loss =10dB. Where, (fmax + fmin)/2 is called center frequency (fc). So, for wideband antennas %bandwidth must be calculated with respect to center frequency.

How antenna gain is measured?

* Antenna gain is measured in decibels as either dBi or dBd. dBi refers to dB away from a theoretical isotropic antenna (0), while dBd refers to dB away from a more real world reference dipole antenna with a gain of 2.15 dB. A theoretical perfectly spherical coverage pattern measured in dBd would be -2.15 dBd.

What is average radiation intensity?

The average radiation intensity: total power radiated by the antenna di- vided by 4π. • Stated more simply, the directivity of a nonisotropic source is equal to the ratio of its radiation intensity in a given direction over that of an isotropic source.

How to measure the radiation pattern of antennas?

Basically, there are two fundamental procedures for measuring the radiation pattern of the antennas. Let us understand each one separately. In this procedure, the primary antenna is placed at a specific location and is of immobile nature. Whereas, the secondary antenna is placed at a certain distance from it.

What are the equipment required for antenna measurements?

The required equipment for antenna measurements include: A positioning system – This system is used to rotate the test antenna relative to the source antenna, to measure the radiation pattern as a function of angle. A block diagram of the above equipment is shown in Figure 1. Figure 1.

What is relative phase in antenna measurements?

Phase Measurements The third antenna measurements section focuses on determining phase information from an antenna’s radiation pattern. The phase is more important in terms of ‘relative phase’ (phase relative to other positions on the radiation pattern), not ‘absolute phase’.

How do I measure the impedance of an RF antenna?

This can be done via a simple power meter, which is a device for measuring RF (radio frequency) power and can be connected directly to the antenna terminals via a transmission line (such as a coaxial cable with N-type or SMA connectors). Typically the receiver is a 50 Ohm system, but can be a different impedance if specified.