1. What is Minimum Distance from Antenna?

The minimum distance from antenna is crucial because it helps maintain the integrity of the signal being transmitted. It is the minimum distance required for far field measurement, ensuring accurate antenna pattern measurements and proper signal reception.

2. How Does the Calculator Work?

The calculator uses the minimum distance formula:

Where:

• \( r_{min} \) — Minimum distance from antenna (m)
• \( D \) — Parabolic reflector diameter (m)
• \( \lambda \) — Wavelength (m)

Explanation: This formula calculates the minimum distance required for far-field measurements, where the electromagnetic wavefront can be considered planar and the antenna radiation pattern is fully developed.

3. Importance of Minimum Distance Calculation

Details: Accurate minimum distance calculation is essential for proper antenna testing and measurement. It ensures that measurements are taken in the far-field region where the radiation pattern is stable and predictable, preventing near-field effects from distorting the results.

4. Using the Calculator

Tips: Enter parabolic reflector diameter in meters and wavelength in meters. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is minimum distance important for antenna measurements?
A: The minimum distance ensures measurements are taken in the far-field region where the antenna's radiation pattern is fully developed and stable, providing accurate results.

Q2: What happens if measurements are taken too close to the antenna?
A: Measurements taken too close (in the near-field) will be distorted by reactive fields and non-planar wavefronts, leading to inaccurate radiation pattern data.

Q3: How does antenna size affect the minimum distance?
A: Larger antennas require greater minimum distances due to the squared relationship in the formula (r_min ∝ D²).

Q4: Does wavelength affect the minimum distance requirement?
A: Yes, shorter wavelengths (higher frequencies) require smaller minimum distances, while longer wavelengths (lower frequencies) require larger distances.

Q5: Are there other factors that might require greater distances?
A: Yes, for very precise measurements or large antennas, additional factors like phase errors may require distances greater than the calculated minimum.