Contents
How are monopole antennas different from dipole antennas?
Monopole antennas, as shown in Figure 6.14, constitute a group of derivatives of dipole antennas. Here, only half of the dipole antenna is needed for operation. A metal ground plane (ideally of infinite size) is used, with respect to which the excitation voltage is applied to the half structure.
Can a monopole antenna be printed on a dielectric substrate?
Sometimes, monopole antennas are printed on a dielectric substrate to make it less fragile and they may be fabricated easily using the printed circuit board technologies. Such antennas are known as printed monopole antennas. They are suitable for various applications such as RFID and wireless networking.
When does a transmission line become an antenna?
Converting a Transmission Line into an Antenna Inefficient radiation 11 Converting a Transmission Line into an Antenna Bending at right angles produces an efficient radiator Optimum radiation occurs when the length is 1/2 of a wavelength Magnetic fields now support each other The Dipole Antenna Fig. 14-10 12
What is the length of a quarterwave monopole antenna?
The approximate, physical length of a printed quarterwave monopole antenna is then = 250/4 = 62.5mm provided that the size of the available ground plane is close to the ideal as discussed above and that the antenna trace is uniformly surrounded by the FR4 substrate.
How does the presence of ground affect an antenna?
The interaction with the ground in this area creates mutual impedances between the antenna and its envi- ronment and these interactions not only modify the feed-point impedance of an antenna, but often increase losses. In the radiating far field, the presence of ground profoundly influences the radiation pattern of a real antenna.
How does the height of an antenna affect the feed point resistance?
In other words, the feed-point resistance of the antenna is affected by the height of the antenna above ground because of mutual coupling be- tween the antenna and the ground beneath it. The electrical characteristics of the ground affect both the amplitude and the phase of reflected signals.
How is AOA measured on a monopole antenna?
If the tracked node knows the AoA for only nodes 1 and 2, the location of the tracked node can be anywhere on an arc connecting nodes 1 and 2. By measuring the AoA of the signal received from anchor node 3, the tracked node can calculate the angle between nodes 2, 4, and 3 as well: