Yagi-Uda Antenna Design Calculator
Calculate Yagi-Uda antenna element dimensions, gain, and impedance for a given frequency and number of elements
Formula
λ = 300/f; G ≈ 10·log₁₀(0.8·N) + 2.15 dBi
How It Works
The Yagi-Uda antenna is a directional antenna consisting of multiple parallel elements, typically made of metal rods, designed to enhance gain and directionality in radio frequency communications. It was originally developed by Japanese engineers Hidetsugu Yagi and Shintaro Uda in the early 20th century. The antenna works by using a driven element (connected to the transmission line) and additional parasitic elements like reflectors and directors to manipulate electromagnetic waves, creating a focused radiation pattern.
Worked Example
Consider a Yagi-Uda antenna designed for 440 MHz with 5 elements: 1 driven element, 1 reflector, and 3 directors. First, calculate the wavelength at 440 MHz: λ = c/f = 3 × 10^8 / 440 × 10^6 = 0.68 meters. The driven element length would be approximately 0.475λ (0.323 meters), reflector length 0.495λ (0.336 meters), and directors around 0.425λ (0.289 meters). Spacing between elements is typically 0.25λ to 0.5λ, which in this case would be 0.17-0.34 meters.
Practical Tips
- ✓Use high-quality, precisely cut conductive materials
- ✓Ensure precise element spacing for optimal performance
- ✓Consider environmental factors like wind and temperature
- ✓Align the antenna for maximum signal reception
Common Mistakes
- ✗Incorrect element length calculations
- ✗Improper element spacing
- ✗Using low-quality materials
- ✗Neglecting environmental interference
Frequently Asked Questions
What is the typical gain of a Yagi-Uda antenna?
Gain varies based on design, but typically ranges from 6-20 dBi depending on the number of elements and frequency.
Can Yagi-Uda antennas work for different frequencies?
Yes, but the element lengths and spacing must be recalculated for each specific frequency range.
Are Yagi-Uda antennas good for long-distance communication?
Yes, they are excellent for long-distance, directional communication due to their high gain and focused radiation pattern.
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