BPM112 is a bidirectional power meter designed for accurate simultaneous measurement of incident and reflected powers up to 30 kW in high-power 2450 MHz industrial applications using an WR340 (R26) rectangular waveguide. Each power meter is calibrated individually.
The BPM integrates a four-port directional coupler with the following components in each of its two channels:
- Zero-bias Schottky diode detector
- Low noise amplifier
- 16-bit A/D converter for sampling detector voltages
- 12-bit D/A converter providing the analog output
- Microcontroller unit (MCU)
- Optional display (common for both channels)
The MCU:
- Controls both A/D and D/A conversions.
- Performs detector nonlinearity and temperature dependence correction.
- Generates the following simultaneous outputs:
- Two analog outputs, one (FWD) corresponding to the forward (incident) power; one (RFL) to the reflected power.
- One digital output (RS232, RS422, or CAN Bus).
The two analog outputs can be:
- voltage output 0 – 10 V; or
- current output 4 – 20 mA.
The desired output type can be switched by the user. Both FWD and RFL outputs are of the same type. The output voltages/currents are linear functions of the microwave powers propagating in the forward and reverse directions of the parent waveguide. The digital outputs provide also internal power sensors temperatures. The RS232 and RS422 outputs have the form of easily readable text streams.
Configuration Options:
- LCD Display: An LCD display that shows the incident (FWD) and reflected (RFL) powers as well as the internal power sensors temperatures. The powers are displayed both numerically and by bar indicators.
- Precision Waveguide: A calibrated assembly consisting of a BPM fixed to a precisely machined parent waveguide with a standard (WR340) or customized length.
- BPM Cable: An extension cable, branching the DC power supply inputs VDC and GND to the power supply and TX, RX, GND pins to standard D9 RS232 connector.
Specifications
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Waveguide type
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WR340 (R26)
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Frequency range
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2425 – 2475 MHz
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Peak working power (options)
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0.5 kW, 1 kW, 3 kW, 6 kW, 10 kW, 30 kW
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BPM Monitor
The BPM is accompanied by the simple LabVIEW-based Windows visualization application BPM Monitor.
BPM Monitor is a program for monitoring and controlling BPM devices. It displays graphs of the incident, reflected and absorbed powers as functions of time. The reflection coefficient magnitude is also displayed in a separate graph. The history of the graphs can be extended to up to 24 hours. All data on graphs can be easily exported to Excel for analysis.
The BPM Monitor also contains a simple RS232 Terminal dialog for setting the internal BPM parameters.
One can perform a more detailed analysis of the generator output waveform with the help of Samples Waveform and FFT Dialog windows, that show the output power as a function of time and its power spectrum, respectively.
For LabVIEW programmers wishing to develop their own applications, there is a BPM library of virtual instruments available. The library is a part of the BPM Monitor installation package.