How do I calculate the required antenna size for a satellite ground station at a given frequency band?
Ground Station Antenna
For GEO satellites (fixed pointing): the dish only needs to be aligned once, and periodic adjustments compensate for satellite station-keeping. For LEO: the antenna must track the satellite across the sky, requiring either a motorized dish (azimuth-elevation pedestal) or a flat-panel electronically steered array. Phased array ground stations can simultaneously track multiple LEO satellites, enabling seamless handover and increased throughput.
| Parameter | GEO | MEO | LEO |
|---|---|---|---|
| Altitude | 35,786 km | 2,000-35,786 km | 200-2,000 km |
| Latency (one-way) | ~270 ms | 50-150 ms | 1-20 ms |
| Coverage per Sat | Full hemisphere | Regional | Local footprint |
| Handover | None | Periodic | Frequent |
| Path Loss (Ku-band) | ~206 dB | 190-206 dB | 170-190 dB |
- Performance verification: confirm specifications against the application requirements before finalizing the design
- Environmental factors: temperature range, humidity, and vibration affect long-term reliability and parameter drift
- Cost vs. performance: evaluate whether the application demands premium components or standard commercial grades
- Interface compatibility: verify impedance, connector type, and mechanical form factor match the system architecture
- Margin allocation: include sufficient design margin to account for manufacturing tolerances and aging effects
Frequently Asked Questions
What is G/T?
G/T (gain-to-noise-temperature ratio) is the figure of merit for a receiving ground station. G/T = antenna gain (dBi) - system noise temperature (dB-K). Higher G/T means better receive sensitivity. For a 1.2 m dish at 12 GHz with 150 K system noise temperature: G = 42 dBi, T_sys = 150 K (21.8 dB-K), G/T = 20.2 dB/K.
What size for different applications?
DTH TV (Ku-band GEO): 0.45-0.9 m dish. VSAT broadband (Ka-band GEO): 0.6-1.2 m. LEO broadband (Starlink user terminal): 0.5 m flat-panel phased array. LEO ground gateway: 2-4 m dish or equivalent phased array. Deep space communication: 34-70 m dish (NASA DSN).