For high power Radio Frequency (RF) systems, power monitoring and sampling, at different junctions is a necessary process for system commissioning, fault debugging and health monitoring. This task is accomplished with the help of directional RF power sensor, mostly imported in India from foreign countries. It acts as a single channel plug-in device in the transmission line of RF systems for providing RF power in forward and reverse directions. A newly designed high power (500 W) directional RF power sensor with dual channels is developed in DAE. It is a thru line coupler and sensor with built-in digital conversion and scaling of data. The converted data is represented in direct milli-dBm unit and is communicated on standard RS422/485 interface. It is compact in size, accurate, cost efficient and indigenous product when compared to imported unit.

The sensor has been developed on the above integrated scheme and offers many advantages, listed below.

Figure 1 : Developed sensor with its schematics showing port details

Introduction: For high power Radio Frequency (RF) systems, power monitoring and sampling, at different junctions is a necessary process for system commissioning, fault debugging and health monitoring. This task is accomplished with the help of directional RF power sensor. It acts as a single channel plug-in device in the transmission line of RF systems for providing RF power in forward and reverse directions. 
This document describes a newly designed high power (500 W) directional RF power sensor with dual channels. It is a thru line coupler and sensor with built-in digital conversion and scaling of data. The converted data is represented in direct milli-dBm unit and is communicated on standard RS422/485 interface. It is compact in size, accurate, cost efficient and indigenous product. It does not need any meter to monitor RF power. Optionally it can be interfaced to a normal computer. It has capability of separating RF powers, propagating in two different directions by virtue of novel coaxial to microstrip coupler. This is useful for measurement of forward and reflected power in a variety of RF power generation and antenna systems. It is a thru-line dual channel sensor thus it can be used for measuring RF power while system is working (without terminating) and monitoring line or load condition in various RF systems. For example, application in solid-state high-power amplifier systems can be quoted, where a huge requirement exists for accurate and reliable measurement of forward as well as reflected powers of the amplifier modules.

Type and Applications

Device Type: Two channel through line directional RF power Sensor
Coupler: Rigid coaxial main line and micro-strip secondary line
Function: Thru-line RF power measurement
Application: Specially suited for large channel embedded RF measurement applications

RF Performance

Frequency Range: 300 MHz to 700 MHz
Power Handling/Withstanding: 1 kW max.
Calibration: Narrow band calibration on single frequency of use
Measurement Range: 5 W to 500 W CW and 20 W to 2 kW Pulsed
Typical Relative Accuracy: ±0.2 dB maximum in full range and ±0.1 dB RMS error
Typical Directivity: 20 dB min (after calibration)

Interface Specifications

Interface Connections: RJ45 socket (8P8C)
Communication: RS485 full/half duplex
Serial Settings: 28800 baud rate, even parity, 8 bit data, single stop bit
Electrical Power Requirement: 9 V to 24 V DC (≤100 mA) via above interface connector 
Daisy Chaining – If required multiple sensors may be daisy chained by using a hub.

Physical Specifications

RF Connectors: N-type connectors (receptacle) for all RF ports
Size with RF connectors: 110 mm x 108 mm x 35 mm (L x W x H)
Size excluding connectors: 70 mm x 108 mm x 35 mm (L x W x H)
Gross Weight: ≤ 800 gm
Enclosure: Passivated Aluminum enclosure

Typical End Users

It is a thru-line dual channel sensor thus it can be used for measuring RF power while system is working (without terminating) and monitoring line or load condition in various RF systems used for strategic applications. For example, application in solid-state high-power amplifier systems can be quoted, where a huge requirement exists for accurate and reliable measurement of forward as well as reflected powers of the amplifier modules.

Manpower Requirement