Technical Principles, Design, and Applications

In the increasingly complex low-altitude security environment, anti-drone systems have become an important component of critical infrastructure, security for major events, and military defense. As the core radio frequency front-end of an anti-drone system, the performance of the power amplifier module directly determines the system's effective operating range, signal quality, and anti-interference capability. Based on years of technical accumulation in the radio frequency and microwave field. chengdu RYX developed modules which can cover 200MHz to 6GHz frequency band and with output power from 10W to 100W, and supports customized customer needs. 

I. Function of Anti-Drone Power Amplifier Modules

An anti-drone power amplifier module is the core of the power amplification in a directed energy jamming system. Its function is to amplify the low-power radio frequency signal generated by the signal source to a sufficient power level, radiating it through a directional antenna to form an effective jamming field in a specific airspace. This jamming can suppress the communication link between the drone and the control station (such as GPS, remote control signals), or deceive its navigation system, forcing the drone to hover, return, or land.

Unlike general-purpose communication power amplifiers, anti-drone power amplifiers need to meet higher requirements: wide bandwidth coverage to cope with multiple drone frequency bands, high linearity to reduce out-of-band radiation, fast power control to adapt to targets at different distances, and excellent heat dissipation design to support long-term continuous operation. 

II. Core Technical Features of  Power Amplifier Modules

1. Ultra-wideband Frequency Coverage:

Our modules adopt a multi-band fusion design, covering major drone operating frequency bands such as 433MHz, 915MHz, 1.2GHz, 1.5GHz (GPS L1), 1.6GHz (GLONASS), 2.4GHz (Wi-Fi/Remote Control), and 5.8GHz. By optimizing the broadband matching network, a VSWR of less than 2.0:1 is achieved across the entire frequency band while ensuring efficiency. 2. Scalable Power Architecture:

Utilizing modular power combining technology, the basic unit provides four standard power levels: 10W, 30W, 50W, 80W, and 100W. Through multi-module spatial or electrical combining, it can be flexibly expanded to higher power to meet interference requirements at different distances (500 meters to 5 kilometers). 

3. High Linearity and Low Noise Design

Low-noise amplification and pre-distortion correction technology are used in the pre-stage of the power amplifier chain to ensure that the third-order intermodulation distortion (IMD3) is below -30dBc at maximum output power, avoiding out-of-band spurious interference with other legal frequency bands. 

4. Intelligent Control Interface

Built-in digital control unit, supporting CAN bus or RS-485 interface, real-time monitoring of power amplifier status (temperature, voltage, reflected power, output power), and over-temperature, over-voltage, over-current, and mismatch protection functions. 

III. Working Principle and Circuit Design Considerations

Anti-UAV power amplifier modules typically adopt a three-stage amplification structure: driver stage, intermediate stage, and final stage power amplification. 

Driver Stage Design: Low-noise GaAs pHEMT or GaN HEMT devices are selected to ensure sufficient gain while controlling the noise figure to within 3dB. The key to this stage is wideband input matching. We employ a Chebyshev multi-section matching network to achieve an input return loss better than 15dB in the 433MHz to 5.8GHz range. 

Intermediate Stage Design: Primarily provides power gain and handles predistortion. We utilize an analog predistortion circuit in this stage, generating a reverse distortion component by detecting the nonlinear characteristics of the final stage power amplifier, effectively compensating for AM-AM and AM-PM distortion in the final stage. 

Final Stage Power Amplification: This is crucial for overall system efficiency. KEDA-MM uses GaN-on-SiC process power transistors, whose electron mobility at high temperatures is more than 5 times that of traditional LDMOS, achieving a power density of 6-8W/mm². Optimal load impedance for each frequency band was determined through load pull testing, and a wideband output matching network was designed. 

Heat Dissipation Design: A 100W module can dissipate 60-70W of heat under continuous wave operation. We employ a layered heat dissipation structure: the power amplifier transistors are directly soldered to a copper-tungsten heat sink using gold-tin solder, and heat is then conducted to a liquid cooling plate via heat pipes. Actual measurements show that the junction temperature of the die can be controlled within a safe range of 125℃ at an ambient temperature of 40℃. 

IV. Key Performance Parameters and Test Methods

1. Frequency Range: 433-5800MHz (Supports continuous full-band coverage or customized band-specific operation).
2.   Output Power: Saturated Output Power: 30W/50W/80W/100W (PEP, 1dB compression point) Linear Output Power: 3dB lower than saturated power (meets third-order intermodulation requirements.
3.    Gain and Flatness: Small Signal Gain: 50±2dB (typical value), In-band Flatness: ±1.5dB (full band).
4.   Efficiency Specifications: Power Added Efficiency (PAE): 40%-55% (varies with frequency and power) , Overall DC-RF Efficiency: ≥35% (including control circuit losses)
5.  Spurious and Harmonic Reduction: Harmonic Suppression: ≤-60dBc (Second and Third Harmonics); Out-of-Band Spurious Reduction: ≤-75dBc (Beyond 10MHz Carrier Spectrum)
6.  Protection Functions: Reflection Power Protection Threshold: Settable (Default 3W),Over-Temperature Protection: Power reduction at 85℃, shutdown at 95℃, Overcurrent Protection: Response time <10μs 

Special attention should be paid during testing, as anti-drone power amplifiers often operate under non-ideal 50Ω loads. We use a load-pulling system to verify the amplifier's stability under a voltage standing wave ratio (VSWR) mismatch of 3:1, ensuring it will not be damaged by antenna impedance changes. 

V. Application Scenarios and System Integration Solutions

1. Fixed Key Target Protection

For fixed facilities such as airports and nuclear power plants, multi-module composite arrays are recommended. For example, four 100W modules can be combined into a 400W transmitting system via a four-way combiner. Combined with an electronically scanned phased array antenna, this can create a 120° azimuth jamming sector with a range of 3-5 kilometers. 

2. Vehicle-Mounted Mobile Jamming System

Due to power supply and heat dissipation limitations, vehicle-mounted platforms are recommended to use our 50W compact module (120×80×25mm). This module uses forced air cooling, supports a wide voltage input of 12V/28V, and can be directly powered by the vehicle battery. Combined with a parabolic or log-periodic antenna, it can be quickly deployed to temporary security sites. 

3. Portable Individual Jamming Equipment

For special operations needs, we have developed a 30W handheld version, weighing no more than 1.5kg. Its built-in lithium battery supports 15 minutes of continuous operation. Utilizing a foldable Yagi antenna, it can accurately jam micro-UAVs within 500 meters. 

4. Multi-Task Integrated RF System

In some high-end applications, our power amplifier modules can be integrated into an all-in-one RF platform, working in conjunction with reconnaissance receivers and signal analysis units. The system can automatically identify UAV signal characteristics, select the optimal interference frequency band and modulation method, and achieve intelligent jamming. 

VI. Customization Service Capabilities

In addition to the standard product line, we offer in-depth customization for specific missions:

Frequency Customization: Optimized design for special frequency bands (such as frequency hopping and spread spectrum signals), providing both narrowband high-efficiency and broadband uniform coverage solutions.

Power Customization: Supports power level customization from 10W to 200W, optimized design based on customer heat dissipation conditions and power supply capabilities.

Interface Customization: Provides multiple control interfaces such as Ethernet, fiber optic, and LVDS for easy integration with existing customer systems.

Environmental Adaptability Improvement: For harsh environments such as high and low temperatures (-40℃ to +65℃), high altitudes, and salt spray, we offer component selection, sealing, potting, and tri-proofing treatments.