Questions & Answers on Antennas

Log-Periodic Antennas vs Yagi Antennas

Nov 29, 2016

Antenna gain is measured in decibels. It is the ratio between the gain of the antenna compared to the gain of an isotropic antenna. An isotropic antenna is a theoretical antenna which radiates power uniformly in all directions. When we calculate the gain of an antenna and compare it to an isotropic antenna the unit of the gain is dBi (i stands for Isotropic antenna). An Isotropic antenna has a 0 d...read more

What are Near Field and Far Field Regions of an Antenna?

Jul 26, 2017

Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas.Conceptually, Log-Periodic Antennas are similar to Yagi Antennas. They can be thought of as two or three element Yagi antennas connected together, each tuned to ...read more

May 22, 2018

When a signal from a transmitter is applied to an antenna, it sends out electromagnetic waves in to free space. The EM field characteristics vary as a function of distance from the antenna. They are broadly divided into two regions, the near-field region, and the far field region.The Near Field Region is the region right next to the antenna. It is defined by the following equation:In this region, ...read more

What is EIRP?

What is the difference between EIRP and ERP?

May 22, 2018

Effective Isotropic Radiated Power or Equivalent Isotropically Radiated Power (EIRP) is a measurement of radiated output power from an ideal isotropic antenna in a single direction.An isotropic antenna is meant to distribute power equally in all directions – When we channel that power into a single direction and calculate the power it is known as EIRP. It will be the maximum power emitted by the a...read more

What is the difference between dBi and dBd?

May 22, 2018

EIRP is the Effective isotropic radiated power is the total power radiated by a hypothetical isotropic antenna in a single direction. It gives the signal strength in the direction of the antenna's strongest beam.ERP is Effective Radiated Poweris the total power radiated by an actual antenna relative to a half-wave dipole rather than a theoretical isotropic antenna. A half-wave dipole has a gain of...read more

What is a Virtual Antenna?

Nov 29, 2016

What are Sector Antennas?

Carles Puente i Baliarda

Mar 21, 2017

Virtual Antenna is the commercial name for the "Antenna-less" technology based on a new generation of tiny components named antenna boosters. Antenna boosters are miniature, surface-mount (SMT), off-the-shelf, components that replace conventional customized PIFA/Printed antennas for mobile/wireless connectivity applications. Being much smaller than the operating wavelength (typically below 1/30 or...read more

What is Antenna Efficiency?

Jul 26, 2017

Asector antennaor "sector panel" is a directional antenna for outdoor applications. They are most often used by Base-Stations and can be seen, hung on cell phone towers. They are long, narrow antennas with high gains. Sector antennas consist of an array of dipoles placed in front of a shaped reflector. The size and shape of the reflector determines the performance of these antennas. The reflector ...read more

Jan 3, 2018

Antenna Efficiency is the ratio of power radiated (Prad) by the antenna to the power supplied (Ps) to the antenna. The efficiency of an antenna is usually measured in an anechoic chamber where an antenna is fed with some power and the strength of the radiated electromagnetic field in the surrounding space is measured.An ideal antenna has 100% antenna efficiency i.e., it transmits all the power fed...read more

What is a Grid Antenna?

How do you measure Antenna Gain?

Jul 26, 2017

A Grid Antenna is a variation of the parabolic/dish antenna. The problem with a dish antenna is that under heavy/moderate wind conditions it moves out of alignment or deforms. This is because it has a large solid surface which is usually perpendicular to the wind flow. Since the reflector of the grid antenna is perforated into a grid, it does not face any issues under heavy wind conditions, as the...read more

What is Antenna Directivity?

Glenn Robb

Jun 21, 2017

While antenna simulations can be an accurate predictor of gain, and duplication of known antennas can produce clones with predictable gain, these methods do not actually measure antenna gain. There are methods of measuring fields close to an RF excited around an antenna, called “near field scanning”, that simulate and predict the gain of an antenna. However, all true measurements of antenna gain c...read more

What are Biconical Antennas?

Aug 13, 2018

Directivity is the measure of the concentration of an antennas's radiation pattern in a particular direction. Directivity is expressed in dB. The higher the directivity, the more concentrated or focussed is the beam radiated by an antenna. A higher directivity also means that the beam will travel further.An antenna that radiated equally well in all directions would be omni-directional and have a d...read more

What are the different types of antenna polarization?

Jul 26, 2017

Biconical antennas (also known as Bowtie or Butterfly antennas) are broadband dipole antennas that are made up of two roughly conical conductive objects, nearly touching at their points. These antennas have dipole like characteristics, with a wider bandwidth achieved due to the double cone elements structure.Bio-Conical antennas have an omni-directional radiation pattern in the H-plane similar to ...read more