For a wireless system, a problem needs to be considered in the 433MHz antenna design. The 433MHz antenna design is a very precise task. A good 433MHz antenna needs to consider issues such as frequency band, impedance, and gain.
The simplest 433MHz antenna design is a whip antenna design, which is a 1/4-wavelength line placed on a ground plane. The most common examples are used in wireless broadcast radios, cable equalization amplifiers, amateur radio stations, and cellular phones.
All antennas, like any other element, have at least two connection points. For whip antennas, there must be a connection point and ground connection, although there is only one circuit trace and one battery in the ground layer area.
The whip antenna and the ground layer combine to form a complete circuit. A magnetic field is established between the whip antenna and the ground wire layer. When current passes through the field, the entire circuit is formed. The ideal ground plane should extend at least 1/4 wavelength around the whip antenna base, or more.
433MHz Antenna Design
The ground plane can be made smaller, but it will affect the performance of the whip antenna. When designing an antenna, the area of the ground plane must be considered.
The quarter whip antenna is not a compact antenna. At 1MHz, in the AM broadcast bandwidth, the quarter wavelength is about 246 feet (or 75 meters), and at 100MHz, in the FM broadcast bandwidth, it is about 30 inches ( 75cm), the higher the frequency, the smaller the length, about 3 inches (7.5cm) at 1000 MHz.
A simple formula for calculating one-quarter stream length is 7500/frequency (MHz), the unit is (cm), or 2952/frequency (MHz), the unit is (inch). This formula is only a starting point because the length can actually be shortened.
If the ground layer is super thick and large, and there is a cladding layer, it is not very close to the ground. If the ground plane is too small, the antenna needs to be lengthened.
The antenna length should be measured from a place close to the ground plane, or from a place where the output is emitted. If the whip antenna is fixed on a box and connected to a transmitter with a smooth wire, the smooth wire will become a part of the antenna.
In order to avoid wire misalignment, coaxial cables are used to connect external antennas. On a circuit board, the equivalent of a coaxial cable is a trace around the ground plane.
The whip antenna is a relatively simple and easy-to-design antenna. It requires a quarter-wavelength antenna perpendicular to the ground plane.
Besides the whip antenna 433MHz antenna design, C&T RF Antennas Inc also provides the Helical 433MHz Antenna Design, Through-hole Mount Antenna Dome 433MHz Antenna Design, Internal 433MHz Antenna Design, etc.
Contact the C&T RF engineering team for more antenna designs.
If you have any antenna questions, please read our ANTENNA FAQ section, if you still cannot get the answer you need, please contact us.
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