A Monopole Antenna is essentially one half of a dipole antenna fixed to a ground plane.
They are used for testing radiated emissions and other electric field measurements under 60 MHz. Antennas like our AM-741 model can be used for MIL-STD-461, CISPR automotive tests, and other standards.
The monopole antenna is often referred to as a rod antenna because its conductor is rod-shaped; it can then be fixed perpendicular to a conductive surface which is used as the ground plane.
Currently we offer only one model, the AM-741 antenna, which can detect frequencies between 9 kHz and 60 MHz. You can change the height of the telescoping rod from 23 cm to 105 cm, and you can also remove it completely, making it much easier to carry with you.
The AM-741 is powered by an internal 6 VDC NimH battery to decrease measurement errors that are usually caused by using an external power cable instead of a battery. It also features an integrated preamplifier for more accurate measurements.
The antenna has a polished aluminium counterpoise which will stand the test of time. As a Shieldingshop customer, you'll also be provided with our exclusive 3 year guarantee – so you have absolutely nothing to worry about.
Each of its antennas are calibrated individually to SAE ARP958 by NIST – we also include the data and appropriate certificate with the product.
The AT-220 antenna stand is our recommended mounting support for the AM-741.
The 41 inch monopole antenna is mandatory for radiated emissions measurements in line with EMC standards. EMC consists of any tests from FAA to Military standards measurements under 60 MHz.
Mono-pole antennas are constructed of a rod-shaped conductor which is then mounted perpendicular to a conductive 'ground plane' surface. When set up in this way, the antenna has an identical radiation pattern to a dipole antenna with twice the volts, constructed in a free space. A dipole antenna has two radiators, whereas the mono pole only has one.
The length of the antenna can be adjusted depending on the wavelength frequency that you want to receive. The antenna can only be used for receiving – it lacks transmitting capabilities. When used for receiving, you can measure the output signal between the ground plane and the antenna's lower end.
With a big enough ground plane, the waves from a monopole transmitter will reflect off the ground plane and will appear to come from an image antenna (which forms the 'missing half' of the what would be – dipole antenna). This adds to the direct-radiation which creates an identical radiation pattern to that of a dipole.
The mono pole antenna oscillates waves of current and voltage along its resonant antenna. Monopoles have twice the gain of a dipole antenna that's two times longer. This is because there isn't any radiation present under the earth ground plane; making the antenna two times more directive.
The AM-741 antenna is normally setup in a screen or shielded room with the EUT (Equipment Under Test) fixed to a ground plane made of metal.
Pioneered in 1895 as the 'Marconi Antenna', the monopole was first discovered by Guglielmo Marconi during an experiment in radio engineering and communication. He found that he could transmit radio waves much further when one side of an antenna was fixed to the earth and the other transmitter was suspended in free space by an overhead wire. Interestingly, the early mobile phones featured a mono pole antenna. The ground plane of the phone was created by the outer casing.