High power microwave Weapons types | directed energy weapons

This article describes High Power Microwave Weapons system with block diagram. It mentions types of high power microwave weapons known as directed energy weapons. The advantages and disadvantages of microwave weapon system are also covered.

There are many different types of weapon systems used to disrupt, degrade or destroy electronic systems or circuits of enemy. The microwave weapon system described here uses electromagnetic radiation in the microwave band to perform this task. Although microwave band ranges from 300 MHz to 300 GHz, existing high power microwave systems operate in 500 MHz to 3 GHz. Research is undergoing to develop the non-lethal weapons around 100 GHz frequency due to its effect on humans. As these microwave weapons use higher energy for its operation and used in directional manner for its operation, they are known as directed energy weapons.

Following are the applications of High Power Microwave Weapon systems.
• To damage/destroy the electronic systems/circuits with minimum or no casualties to the human beings.
• To suppress air defence systems of the enemy.
• To target chemical/biological weapon facilities of the enemies as HPM weapons do not release deadly toxins.

High Power Microwave Weapon System Block Diagram

high power microwave weapon system block diagram

The figure-1 depicts typical block diagram of high power microwave weapon system. As mentioned it consists of following modules.
• Pulse Power Source
• HPM Source
• Antenna

Pulse power source consists of power supply and Pulse generator. Function: The pulse power generators should deliver short and intense electrical pulses of 1 MVolt or more. It should have pulse duration of less than 1 µs. There are many ways this can be achieved as mentioned below which depends mainly on type of HPM source to be used.
• Capacitor banks based charging process which converts slow rise low voltage signal to fast rise high voltage signal.
• Inductor charging delivers high repetition rate of few Hz or more.
• Use of flux compression generator. Here magnetic coil is compressed either by explosive or magnetic forces which leads to sharp rise current pulse.

HPM sources are of two types viz. impulsive sources and linear beam sources.
• Impulsive sources: In this type, pulsed microwave energy is generated by charging antenna or transmission line or tuned circuit directly and later make them ring for multiple cycles by closing switch.
Example: Ultra-wide band sources

• Linear beam sources: In this type, microwave energy is generated by converting kinetic energy of electron beam to electromagnetic energy of microwave beam.
Examples: Klystrons, TWT (Travelling Wave Tube), BWO (Backward Wave Oscillator), Magnetron, CFA (Cross-Field Amplifier), Virtual Cathode Oscillator, Gyrotron, Split Cavity Oscillator, Free electron laser, Orbitron Microwave Maser

Antenna is used for transmission of microwave frequency to the intended target. It is used as interface between atmosphere and microwave source.

Types of High Power Microwave Weapons

Following are the two main types of High Power Microwave Weapons.
• Narrow band HPM
• Ultra-wide band HPM

Narrow band HPM radiates all microwave energy within few percent of centre frequency, typically in the range of tens to hundreds of MHz. It uses high power compare to ultra-wide band HPM.
Advantages: • It has better transmission characteristics. •  Fewer problems with fratricide (friendly fire). • 
Disadvantages: • Prior knowledge of target material to decide optimum microwave frequency of the microwave weapon. • This system is effective on certain class of targets.

Ultra-wide band HPM radiates energy over the range which is hundreds of MHz to several GHz.
Advantages: • It can be used for wide range of targets. • It do not require prior knowledge of absorption characteristics of the target.
Disadvantages: This type has shorter range capabilities due to low radiated power and poor transmission characteristics compare to Narrow band HPM.

Advantages of High Power Microwave Weapon System

Following are the benefits or advantages of High Power Microwave Weapon System:
• Speed of light operation and hence will deliver results in seconds.
• Not affected by weather and atmospheric conditions.
• It is effective over large areas which depends on beam divergence, transmit power and distance from target.

Disadvantages of High Power Microwave Weapon System

Following are the disadvantages of High Power Microwave Weapon System:
• Uncertaity of assessment of damage occurred.
• It has short range of coverage compare to high energy based laser weapon systems.

RF and Wireless Terminologies