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The quarter wave antenna is a single element antenna fed at one end that behaves as a dipole antenna. It is formed by a conductor in length λ/4. It is fed in the lower end, which is near a conductive surface which works as a reflector.
This calculator can be used to design a Quarter Wave Ground Plane antenna, with radials. The radiating element is a quarter wave (λ/4) and the radials are 12% longer. There are usually four radials, three being a minimum, but you could use up to six.
“Therefore, we deduce the antenna gain of a quarter-wave monopole antenna above virtual ground as 5.31 dB which is little bit more than twice the gain of a center-fed half-wave dipole antenna that is 2.16 dB.”
Resonant frequency, impedance, and gain of quarter wave ground plane antenna as the radial angle is changed. The first thing to notice is that the resonant frequency shifted, even though the antenna elements were the same length for each case.
Example Calculations. A quarter wave (λ/4) antenna designed for 20 meter applications (15 MHz) has a length of 3.3 meters. The length of radials, assuming a 10% increase, is 3.6 meters. This assumes a velocity factor of 0.66.
This type of antenna is called the quarter-wave (λ/4) monopole antenna. Most antennas on the PCB are implemented as quarter-wave antennas on a copper ground plane.
26 lut 2022 · I built a quarter-wave wave ground plane for 403 MHz, with the elements about 18 cm (7 inches) long, with radials that are about 15% longer. Amateur Radio/AIS Antenna. I also built a 145 MHz amateur band antenna for receiving Amateur satellites.
