Antenna Frequency
Definition
The centre frequency of the radar pulse, typically expressed in megahertz. Higher frequencies give finer resolution but penetrate less deeply. Lower frequencies penetrate further but resolve smaller targets less clearly.
- Unit
- Megahertz (MHz)
- Higher frequency
- Finer resolution, shallower penetration
- Lower frequency
- Deeper penetration, coarser resolution
- Instrument
- Ground-penetrating radar (GPR)
Common questions
How does an investigator choose antenna frequency for a search?+
The choice trades off target depth against target size: a shallow burial or small object search favours a higher-frequency antenna for detail, while a deep or large target such as a foundation or grave shaft favours a lower frequency to reach the needed depth.
Can a single GPR survey use more than one antenna frequency?+
Yes. Some surveys run a lower-frequency pass to establish depth and general subsurface structure, then a higher-frequency pass over flagged areas to resolve fine detail on a promising anomaly.
Related terms
- Dielectric Permittivity
- A soil's capacity to store and transmit electric field energy. Higher water content raises permittivity and slows the radar wave. The contrast...
- Hyperbolic Anomaly
- The characteristic arch shape that point-like or cylindrical subsurface targets produce on a radargram. As the antenna passes over a discrete reflector...
- Radargram
- The cross-sectional image produced by a GPR survey. The horizontal axis represents distance along the survey line; the vertical axis represents two-way...
- Two-Way Travel Time (TWT)
- The time from transmission of a pulse to receipt of its reflection. Depth is calculated as: depth = (velocity × TWT) /...
- Velocity Calibration
- The process of estimating the true electromagnetic wave velocity in the survey soil, usually by fitting a hyperbola to a known reflector...