Why I Built This
What We Want to Measure
RF Test Setup
Measuring Small-Signal Gain
Measuring Compression
Adding an ESP32
Thermal Monitoring
Why This Is Useful
Expected Results
Important RF Safety Note

Published September 5, 2026

RF Power Amplifier Test Bench with Mini-Circuits ZVE-3W-183+

Build a practical microwave RF test bench around the Mini-Circuits ZVE-3W-183+ high-power amplifier. The project combines a 5.9–18 GHz signa

IntermediateWork in progress16

RF Power Amplifier Test Bench with Mini-Circuits ZVE-3W-183+

Things used in this project

Hardware components

Mini-Circuits ZVE-3W-183+

RF signal generator / microwave synthesizer

RF input source

RF power

50 Ω RF atten

50 Ω RF termination, ≥3 W

Input/output level control and protection

Directional coupler

Optional forward/reflected-powe

DC bench power supply, 13–18 V

Amplifier power source

Current/voltage monitor

DC power consumption measurement

ESP32 deve

Environ

DS18B20 temperature se

Optional heatsink temperature monitoring

5.1 V/3.3 V regulator

ESP32 sensor supply

SMA coaxial cables rated for 18 GHz

RF interconnection

SMA attenuator set

Level adjustment

RF DC block

Optional protecti

Cooling fan

Additional thermal

50 Ω load

RF output load during ben

Software apps and online services

Arduino IDE

Python 3

Jupyter Notebook

NumPy

pandas

Matplotlib

Optional PyVISA for instrument control

VNA manufacturer's mea

Serial terminal

Hand tools and fabrication machines

SMA torque wrench

Digital multimeter

Oscilloscope

Soldering iron (generic)

Wire cutter and stripper

Small screwdrivers

Drill and mounting hardware

Bench vise

3D printer, optional

CNC mill

Story

Why I Built This

Microwave amplifiers become much more interesting when you stop looking at them as a single gain number.

A broadband amplifier may provide excellent gain at one frequency and behave differently at another. As the input level increases, gain compression becomes important, the DC power consumption becomes significant, and thermal conditions can affect repeatability.

The Mini-Circuits ZVE-3W-183+ is a good device for demonstrating these effects because it covers 5.9 to 18 GHz and provides approximately 35 dB typical gain. Mini-Circuits specifies +34 dBm typical output power at 1 dB compression and +35 dBm typical saturated output power at 3 dB compression. The amplifier is a Class-A, four-stage design with internal voltage regulation.

This project turns the amplifier into the center of a small microwave characterization bench.

What We Want to Measure

The basic experiment measures:

Frequency response
Small-signal gain
Input and output VSWR
Output power versus input power
Approximate 1 dB compression point
DC voltage and current
Heatsink temperature
Gain variation across the 5.9–18 GHz range

The manufacturer's typical data shows that gain is not perfectly constant across the band. For example, the published typical data gives approximately 36.1 dB at 5.9 GHz, 34.6 dB at 7 GHz, 33.4 dB around 9–12 GHz, and approximately 33.8 dB at 18 GHz.

That makes this device useful for demonstrating a real engineering concept: broadband does not mean perfectly flat.

RF Test Setup

The simplest setup is:

Signal Generator → Attenuator → ZVE-3W-183+ → Attenuator → Power Sensor / Spectrum Analyzer

For gain measurements, a VNA can be inserted into the measurement workflow.

A suitable VNA should support the frequency range being tested. If the instrument only reaches a lower frequency, simply limit the experiment to the overlapping range rather than extrapolating the amplifier's performance.

The attenuator at the amplifier input is particularly important. The manufacturer's maximum input RF power rating is +20 dBm. The amplifier has approximately 35 dB gain, so an input signal near the maximum rating could theoretically produce an output far beyond the intended operating region.

For this reason, start with a much lower input level and increase the signal gradually while monitoring the output.

Measuring Small-Signal Gain

Start at a low input power where the amplifier is clearly operating in its linear region.

For example:

Frequency: 6 GHz
Input power: approximately −20 dBm
Measure output power
Calculate::

Gain = POUT − PIN

If the measured output is approximately +14 dBm, the measured gain is approximately:

14 dBm − (−20 dBm) = 34 dB

Repeat the measurement at several frequencies.

A useful sweep is:

6 GHz7 GHz8 GHz9 GHz10 GHz12 GHz14 GHz16 GHz18 GHz

The resulting graph provides a much more useful picture than a single gain measurement.

Measuring Compression

Next, select one frequency, such as 10 GHz.

Increase the RF input power in small steps while recording output power.

At low input levels, output power should increase approximately 1 dB for every 1 dB increase in input power.

As the amplifier approaches compression, the output increase becomes smaller.

The 1 dB compression point is reached when the measured output power is approximately 1 dB below the extrapolated linear response.

Mini-Circuits specifies a typical output power at 1 dB compression of +34 dBm across the specified frequency range, although actual bench measurements can differ from typical specifications.

Adding an ESP32

The ESP32 is not used to generate the 18 GHz RF signal.

Instead, it acts as the monitoring controller.

It can record:

Supply voltage
Supply current
DC input power
Heatsink temperature
Test timestamp

This separation is important. The microwave path remains a 50 Ω RF system, while the ESP32 handles low-frequency instrumentation.

The DC input power can be calculated as:

PDC = VDC × IDC

For example, at 15 V and 2.2 A:

PDC ≈ 33 W

This is substantially higher than the RF output power, which is why thermal management matters for a Class-A amplifier.

The manufacturer's specification lists a typical supply current of 2.2 A and specifies that the supply should be capable of delivering 3 A during startup.

Thermal Monitoring

Attach a temperature sensor to the heatsink rather than directly to an RF connector or the microwave enclosure.

The temperature should be logged together with RF measurements.

This makes it possible to answer a practical question:

Does the measured gain or output power change as the amplifier heats up?

The experiment should not be used to intentionally exceed the manufacturer's temperature limits. The specified maximum base-plate temperature is 85°C.

Why This Is Useful

This project is useful for RF engineers, students, and microwave enthusiasts because it demonstrates the complete measurement chain rather than just the amplifier.

It also shows an important engineering principle:

A high-frequency RF system is not only about the RF device.

Cables, attenuators, connectors, calibration, impedance matching, power measurement, thermal conditions, and DC power delivery can all affect the final result.

The same measurement approach can later be adapted to other RF amplifiers.

Expected Results

The expected results should be compared against the manufacturer's published typical data rather than treated as guaranteed limits.

The datasheet specifies:

Frequency range: 5.9–18 GHz
Typical gain: 35 dB
Gain flatness: ±1.4 dB typical
Input VSWR: 1.5:1 typical
Output VSWR: 1.2:1 typical
Output power at 1 dB compression: +34 dBm typical
Saturated output power: +35 dBm typical
Noise figure: 5.5 dB typical
OIP3: +44 dBm typical
Supply voltage: 13–18 V
Typical supply current: 2.2 A

These are useful reference values, but the actual result depends on frequency, temperature, instrumentation, calibration, cables, connectors, and test conditions.

Important RF Safety Note

3 W of RF power at microwave frequencies is not a casual signal level.

Do not operate the amplifier with an unknown load or an improperly connected RF path. Use appropriate 50 Ω components, rated attenuators, terminations, cables, and measurement equipment.

Always follow the amplifier manufacturer's operating limits and the safety requirements of the laboratory.

The purpose of this project is controlled RF measurement, not free-space radiation.

Code

```cpp
/*
  ZVE-3W-183+ RF Amplifier Test Bench
  ESP32 monitoring firmware

  Functions:
  - Reads DC supply voltage
  - Reads DC current from an analog current-sensor output
  - Reads DS18B20 heatsink temperature
  - Calculates DC input power
  - Sends CSV data to the PC

  IMPORTANT:
  The analog scaling and current-sensor conversion must be
  calibrated for the actual hardware used.
*/

#include <OneWire.h>
#include <DallasTemperature.h>

#define TEMP_PIN 4
#define VOLTAGE_PIN 34
#define CURRENT_PIN 35

OneWire oneWire(TEMP_PIN);
DallasTemperature sensors(&oneWire);

// Example ADC reference.
// Calibrate this value for the actual ESP32 board.
const float ADC_REF = 3.3;
const int ADC_MAX = 4095;

// Example voltage-divider ratio.
// Change these values to match the actual divider.
const float R_TOP = 100000.0;
const float R_BOTTOM = 22000.0;

// Example current sensor parameters.
// Replace with the actual sensor's transfer function.
const float CURRENT_ZERO_V = 1.65;
const float CURRENT_SENSITIVITY = 0.066;   // V/A example only

void setup()
{
  Serial.begin(115200);

  analogReadResolution(12);

  sensors.begin();

  Serial.println("time_ms,voltage_V,current_A,power_W,temperature_C");
}

float readVoltage()
{
  int raw = analogRead(VOLTAGE_PIN);

  float adcVoltage =
      (raw * ADC_REF) / ADC_MAX;

  float inputVoltage =
      adcVoltage * ((R_TOP + R_BOTTOM) / R_BOTTOM);

  return inputVoltage;
}

float readCurrent()
{
  int raw = analogRead(CURRENT_PIN);

  float sensorVoltage =
      (raw * ADC_REF) / ADC_MAX;

  float current =
      (sensorVoltage - CURRENT_ZERO_V)
      / CURRENT_SENSITIVITY;

  if (current < 0)
    current = 0;

  return current;
}

void loop()
{
  sensors.requestTemperatures();

  float temperature =
      sensors.getTempCByIndex(0);

  float voltage =
      readVoltage();

  float current =
      readCurrent();

  float power =
      voltage * current;

  Serial.print(millis());
  Serial.print(",");

  Serial.print(voltage, 3);
  Serial.print(",");

  Serial.print(current, 3);
  Serial.print(",");

  Serial.print(power, 3);
  Serial.print(",");

  Serial.println(temperature, 2);

  delay(1000);
}
```

```cpp
/*
  ZVE-3W-183+ RF Amplifier Test Bench
  ESP32 monitoring firmware

  Functions:
  - Reads DC supply voltage
  - Reads DC current from an analog current-sensor output
  - Reads DS18B20 heatsink temperature
  - Calculates DC input power
  - Sends CSV data to the PC

  IMPORTANT:
  The analog scaling and current-sensor conversion must be
  calibrated for the actual hardware used.
*/

#include <OneWire.h>
#include <DallasTemperature.h>

#define TEMP_PIN 4
#define VOLTAGE_PIN 34
#define CURRENT_PIN 35

OneWire oneWire(TEMP_PIN);
DallasTemperature sensors(&oneWire);

// Example ADC reference.
// Calibrate this value for the actual ESP32 board.
const float ADC_REF = 3.3;
const int ADC_MAX = 4095;

// Example voltage-divider ratio.
// Change these values to match the actual divider.
const float R_TOP = 100000.0;
const float R_BOTTOM = 22000.0;

// Example current sensor parameters.
// Replace with the actual sensor's transfer function.
const float CURRENT_ZERO_V = 1.65;
const float CURRENT_SENSITIVITY = 0.066;   // V/A example only

void setup()
{
  Serial.begin(115200);

  analogReadResolution(12);

  sensors.begin();

  Serial.println("time_ms,voltage_V,current_A,power_W,temperature_C");
}

float readVoltage()
{
  int raw = analogRead(VOLTAGE_PIN);

  float adcVoltage =
      (raw * ADC_REF) / ADC_MAX;

  float inputVoltage =
      adcVoltage * ((R_TOP + R_BOTTOM) / R_BOTTOM);

  return inputVoltage;
}

float readCurrent()
{
  int raw = analogRead(CURRENT_PIN);

  float sensorVoltage =
      (raw * ADC_REF) / ADC_MAX;

  float current =
      (sensorVoltage - CURRENT_ZERO_V)
      / CURRENT_SENSITIVITY;

  if (current < 0)
    current = 0;

  return current;
}

void loop()
{
  sensors.requestTemperatures();

  float temperature =
      sensors.getTempCByIndex(0);

  float voltage =
      readVoltage();

  float current =
      readCurrent();

  float power =
      voltage * current;

  Serial.print(millis());
  Serial.print(",");

  Serial.print(voltage, 3);
  Serial.print(",");

  Serial.print(current, 3);
  Serial.print(",");

  Serial.print(power, 3);
  Serial.print(",");

  Serial.println(temperature, 2);

  delay(1000);
}
```

Credits

Robert Fletcher

20 projects • 1 follower

Senior semiconductor engineer at AVAQ Semiconductor. With extensive experience in electronic components, supply chain solutions & sourcing.

RF Power Amplifier Test Bench with Mini-Circuits ZVE-3W-183+

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Why I Built This

What We Want to Measure

RF Test Setup

Measuring Small-Signal Gain

Measuring Compression

Adding an ESP32

Thermal Monitoring

Why This Is Useful

Expected Results

Important RF Safety Note

Schematics

Diagram 1 — RF signal path

Diagram 2 — DC and monitoring system

Code

DC/temperature monitoring firmware

DC/temperature monitoring firmware

Credits

Robert Fletcher

Comments

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RF Power Amplifier Test Bench with Mini-Circuits ZVE-3W-183+

RF Power Amplifier Test Bench with Mini-Circuits ZVE-3W-183+

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Why I Built This

What We Want to Measure

RF Test Setup

Measuring Small-Signal Gain

Measuring Compression

Adding an ESP32

Thermal Monitoring

Why This Is Useful

Expected Results

Important RF Safety Note

Schematics

Diagram 1 — RF signal path

Diagram 2 — DC and monitoring system

Code

DC/temperature monitoring firmware

DC/temperature monitoring firmware

Credits

Robert Fletcher

Comments

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