The interference effects of GaN and LDMOS are inconsistent. The core differences stem from the differences in power-added efficiency, linearity, frequency characteristics and spurious suppression capabilities, resulting in significant differences in scenario adaptability in radio frequency interference scenarios such as drone countermeasures.
Typical Interference Scenarios and Adaptation Recommendations
Drone Countermeasures (Multi-band, High-frequency, High-power)
Preferred GaN: Wideband coverage (2.4G/5.8G/Satellite navigation), high efficiency resulting in longer continuous interference time, and optimized linearity with DPD, suitable for portable/vehicle-mounted devices.
Secondary LDMOS: Provides cleaner narrowband interference in low-frequency bands such as 2.4G, suitable for fixed-site deployment, and lower cost.
Communication Suppression (Narrowband, Low Spurious Emissions)
Preferred LDMOS: Linearity advantage reduces adjacent channel interference, lowering the risk of being monitored and located, suitable for scenarios with high compliance requirements.
Cost-Sensitive/Low-to-Medium Power
Preferred LDMOS: Mature technology, 30%-50% lower cost, simple maintenance, suitable for mass deployment of low-to-medium power interference nodes.
Calculation Example (Quantizing the Difference in Interference Effect)
Assuming an input power of 100W, PAE: GaN 65%, LDMOS 55%, then:
GaN Output Power: 100W ÷ (1-65%) × 65% ≈ 185.7W
LDMOS Output Power: 100W ÷ (1-55%) × 55% ≈ 122.2W
Conclusion: Under the same input, GaN has approximately 52% higher interference power and a wider coverage area.
Implementation Considerations
GaN Systems: DPD linearization, strict power-on timing control, and efficient thermal management are essential; otherwise, spurious/reliability issues can easily affect interference effectiveness.
LDMOS Systems: Utilizing hard compression characteristics simplifies linearization design, focuses on low-frequency optimization, controls cost and heat dissipation, and is suitable for large-scale deployment.