English
Nov 06 , 2024
The Lora Yagi Antenna, commonly known as a Yagi antenna, is an end-fire antenna consisting of an active element (usually a folded dipole), a passive reflector, and several passive directors arranged in parallel. In the 1920s, this antenna was invented by Hidetsugu Yagi and Shintaro Uda of Tohoku University in Japan. It is often referred to as the "Yagi-Uda antenna," abbreviated as "Lora Yagi Antenna."
Simple structure, lightweight, and sturdy
Convenient feed
High gain, strong directivity, anti-interference, and long working distance
Simple construction, small size, readily available materials, low cost, small wind resistance, lightweight and robust, easy to set up
Frequency band coverage: The Lora Yagi Antenna is suitable for HF (3~30 MHz), VHF (30~300 MHz), and UHF (300~3000 MHz) frequency bands, with VHF and UHF bands falling under the VHF frequency band. This means that the Lora Yagi Antenna can meet the requirements of VHF communication.
High gain and directivity: Under ideal conditions, the Lora Yagi Antenna can achieve a high gain level (up to 19 dB in certain situations) and has strong directivity. This enables the Lora Yagi Antenna to focus the signal more effectively in VHF communication, improving communication quality and reducing interference.
Convenient to carry and set up: The Lora Yagi Antenna's simple, lightweight, and sturdy structure makes it easy to carry and set up. This is a significant advantage for VHF communication systems that require quick deployment.
Radar system compatibility: The high gain and directivity of the Lora Yagi Antenna make it an ideal choice for radar systems. Whether it is meteorological radar, early warning radar, or speed radar, the Lora Yagi Antenna can provide clear radar images and accurate measurement results.
Improving detection performance: In radar systems, the Lora Yagi Antenna can collect and process radar signals more effectively, enhancing the radar's detection performance and anti-interference capability. This is crucial for improving the overall performance and reliability of radar systems.
The working principle of the Lora Yagi Antenna is as follows (using a three-element antenna for reception as an example): The director is slightly shorter than half the wavelength, the main element is equal to half the wavelength, and the reflector is slightly longer than half the wavelength. The spacing between the elements is a quarter wavelength. At this point, the director exhibits "capacitive" characteristics towards the induced signal, with the current leading the voltage by 90°. The electromagnetic wave induced by the director radiates towards the main element, and the radiated signal traveling a quarter wavelength delays by 90°, effectively canceling out the previously induced "lead," thus the two are in phase and the signal is reinforced. The reflector is slightly longer than half the wavelength, showing inductive characteristics, with the current lagging by 90°, and further delayed by 90° during radiation to the main element, totaling a 180° delay, thus nullifying it. This enhances one direction while weakening the other, thus strong directionality is achieved. The same process applies to the transmission state.
