www.cpii.com/bmd

3475 SERIES

Magnetron Transmitter

Communications & Power Industries

Magnetron Transmitter

FEATURES:

• Up to 400 kW peak power

• Compatible with multiple magnetrons

• VSWR protection

• Modular design for ease of customization

• Touch screen local control with Ethernet

connectivity for remote control and monitoring

• Air cooled

BENEFITS:

• CPI BMD Magnetrons and modulators ensure

compatible performance

• Transmitter is compatible with magnetrons at

various power levels and frequencies

• Easy to use and user friendly

• Built in diagnostics and BIT for local or remote

troubleshooting.

APPLICATIONS:

• Instrumentation radar

• Weather radar

• EMI/EMC field testing

The VPW3475 magnetron transmitter is devel-

oped as a fully integrated magnetron system

operating up to 400 kW peak power. This micro-

wave transmitter uses a CPI coaxial magnetron as

its RF output device. The frequency of operation

is magnetron dependent. Any CPI magnetron

with RF power range up to 400 kW can be used in

this transmitter. CPI provides any modiﬁcations

required for the particular magnetron chosen. CPI

is able to furnish a compact, user-friendly, micro-

wave power source which is also cost effective.

The transmitter cabinet contains the high voltage

power supply, magnetron, solid state switch, and

the high voltage tank assembly which includes the

pulse transformer, energy storage high voltage

capacitor, and ﬁlament power supply and control

system for local or remote operation. CPI provides

a complete cabinet with a touch screen controller

and dual-directional coupler which is part of the

CPI control system for monitoring forward and

reﬂected power. Depending on the options

selected CPI can also provide RF isolators and

servo-tuners for the magnetron if desired.

www.cpii.com/bmd

3475 SERIES

Magnetron Transmitter pg.2

Communications & Power Industries

Magnetron Transmitter

The high voltage power supply is a 19 inch tray

inside the cabinet. It is completely self-protected

with over current and input under/over voltage

circuits. The ﬁlament power supply needed to

operate the magnetron is contained in this unit.

All external interface and control is done in this

supply. Cooling is accomplished by internal fans.

Cathode pulsing is done by a completely

solid-state array of IGBT switch boards that is

driven by the control interface board in the high

voltage power supply. This switch inherently

limits current and pulse energy by design, no

external circuitry is required for these functions.

The IGBT switch is also a current controlled

switch, set by a bias voltage from the high voltage

power supply control interface board. The volt-

age across the switch will automatically change as

the voltage across the magnetron changes due to

frequency and temperature changes. Shifting

from magnetron to magnetron only requires an

adjustment of the drive voltage. This switch will

inherently limit arc current in the event of a mag-

netron HV arc. The limit is less than twice the

normal operating current in the event of a com-

plete short circuit. The switch assembly has inter-

nal fans to cool the switches.

All high voltage is contained in a sealed tank. The

pulse transformer that steps up the high voltage

power supply output to the required magnetron

voltage, the storage capacitor bank to supply the

energy during the pulse, and the magnetron

ﬁlament connections are all contained in this tank.

The magnetrons are mounted at the top of the

enclosure for easy access. A fan is provided to

cool the magnetron.

Options:

• A servo-ampliﬁer can be supplied to provide

frequency control using computer commands.

• An RF isolator or circulator can be provided for

VSWR protection

Instrumentation and Control

Front Panel Control and Display

The magnetron transmitter has a touch screen

computer control system that accepts control

inputs and provides status, fault/alarm conditions,

and metered parameter information. This infor-

mation is available on the front panel screen of the

transmitter and also via an Ethernet connector.

The table on page 3 deﬁnes the speciﬁc control

functions, monitored test points on the front

panel, transmitter operating status, fault/alarm

conditions, and metered voltages, currents, and

operating times.

The front panel consists of the touch screen that

allows for individual controls and as well for oper-

ation remotely through the Ethernet connection.

Analog test points are available for diagnostic and

performance assessment on the rear panel. These

test points are buffered to allow the use of stan-

dard test equipment such as oscilloscopes, RF

spectrum analyzers, and RF power meters.

The remote interface utilizes an Ethernet IP

address with CPI standard protocol and command

set. All the front panel information and functions

that are available on the control panel are also

available via the remote interface. In order for the

transmitter to be remotely operated, the Front

Panel local/remote switch must be commanded to

remote. The analog test points are not remotely

available.