SynthHD Mini: 10MHz – 15GHz Microwave Generator


The SynthHD Mini is the smallest 10MHz to 15GHz RF Signal Generator in the world.  Expect excellent performance despite the ultra-small size and price of this device.

Tune any frequency between 10MHz and 15GHz in 0.01Hz resolution.  Adjust calibrated amplitude in 0.01dB resolution up to +20dBm and across more than 30dB of range.  Perform FM, AM, Pulse, Sweep, and List Modulations.  See the Tabs below to download a full datasheet and other documents.

Windfreak Technologies has set the bar on microwave radio frequency generators for quality, size, and price.  As always, our products are designed and manufactured in the USA!

In Stock.  Ships within 5 days.

Microwave Signal Generator, SynthHD Mini

HD stands for high definition:

  • 10 MHZ to 15 GHZ in 0.01 Hz steps
  • -13 dBm to +20 dBm (typical) in 0.01 dB steps
  • Select internal 27MHz reference or use external 10-100MHz reference
  • Pulse, AM, and FM internal modulation including FMCW radar chirp
  • Pulse Modulation with 1uS minimum width and 1uS resolution
  • Pulse, AM, and FM external modulation from DC – 10KHz
  • Powerful Trigger modes allow external triggering of most functions without a PC connected
  • Linear, %, and list mode (frequency and amplitude hopping) sweeps
  • Save all settings to the device for use without a PC
  • 32 bit ARM processor onboard which is Arduino compatible
  • Labview GUI executable and source code (pictured below) included with purchase
  • Windows, Linux, and Android compatibility
  • Designed and manufactured in the USA with maximized value and cost ratio

Contact us for custom firmware and hardware options.

Weight 1.5 lbs
Dimensions 7 × 5 × 2 in

Features List

  • Calibrated RF output
  • Ultra-small, milled enclosure roughly 1.6 X 1.6 X 0.5 inches
  • Open source Labview GUI software control
  • Run hardware functions with or without a PC
  • USB or UART control via USBC connector
  • Trigger, Modulation via USBC connector
  • Reference Input or Output via USBC
  • Open source USB breakout board sold separately
  • 0.01dB amplitude resolution
  • 0.01Hz frequency resolution
  • 100uS RF lock time standard
  • 250uS per step typical sweep speed
  • Up to +20dBm output power
  • Over 30dB of power control
  • 2.5ppm internal reference accuracy
  • -115dBc/Hz phase noise at 1GHz @ 10KHz offset
  • Internal and External FM, AM, Pulse Modulation
  • External sweep, step, and modulation trigger
  • 500 point frequency and amplitude hop table
  • 32-bit ARM processor onboard
  • Low Power 400mA typical
  • Designed, manufactured, and supported in the USA


1 USB and UART Warning

The SynthHD Mini was designed to work with a USB 2 port, or a USB 2 cable which can be plugged into either a USB 2 or USBC port. Use a USB 3 cable only when tapping into the Power, UART, Reference and Trigger signals for 3.3V – 5V COM port control of the SynthHD Mini with your own microcontroller circuit. Using a USB 3 cable attached to a USB 3 port on a PC may have unknown consequences as the PC is not designed to see the SynthHD Mini UART and other signals and vv. See UART app note for UART usage instructions.

A USB 2 to USB 3 breakout adapter board is available for easier access to the UART and Trigger and Modulation connections.

UART and Trigger signals are isolated with series 500 ohm resistors to protect the hardware.

2 Characteristics

2.1 Electrical Characteristics

Supply VoltageSuggested 300mA minimum4.755.5V
Supply Current0dBm RF at 1GHz400mA
Standby Supply CurrentRF output OFF20mA
RF Output Frequency Range10-15000MHz
Calibrated Frequency Range1015000MHz
RF Output Power MaximumSee graph20dBm
RF Output Power MinimumSee graph-13dBm
RF OFF Output Power100% shutdown of RF section-80dBm
RF Output Frequency ResolutionDefault is 0.1Hz selectable by Channel Spacing Setting0.01Hz
RF Output Power Resolution0.01dB
Output Temperature Variation0 to +70C, 1GHz, 0dBm+/- 0.6dB
RF Output Impedance50
Internal Reference Frequency27MHz
Internal Reference Tolerance2.5ppm
TriggerInternally pulled up 5V tolerant-0.33.35V
UART3.3V native, 5V tolerant-0.33.35V
RF ConnectorNormally Polarized Female SMA

2.2 Thermal Operating Characteristics

-4030°CWithout airflow or heat sinking.
-4075 Internal°CQuery internal temperature sensor with software and keep below 75C with airflow, heat sinking, or limited duty cycle.

3. Software and Hardware

3.1 Open Source Software GUI

The included GUI is written in LabVIEW™ and source code vi’s are supplied with purchase of
hardware. Also supplied is a Windows installer for users that do not own the LabVIEW™ development
environment. All functions of the hardware are accessible by the software. Custom software developers
see the website for a download of the easy to use API document.

SynthHD Mini Software Tab

SynthHD Mini Control GUI

3.2 USBC Connector Pinout

The USBC connector is used in an unconventional way to allow access to UART, Reference,
Modulation and Trigger Signals. As mentioned above, avoid connecting this device directly to a USB 3
port on your PC. Use a USB 2 extension cable instead.

Signal NameUSBC Pin #Description
VBUSA4, B4, A9, B9+5V Power
USB D-A7, B7USB 2.0 differential pair
USB D+A6, B6USB 2.0 differential pair
GNDA1, B1, A12, B12Ground
UART TxA11, B11UART SynthHD Mini TX (hook to host RX)
UART RxA10, B10UART SynthHD Mini RX (hook to host TX)
ReferenceA2Reference I/O (Warning: Single Sided)
TriggerB2Trigger Input (Warning: Single Sided)

3.3 Recommended UART and Trigger Breakout Circuit

USBC Recommended Breakout Schematic

USBC Recommended Breakout PCB Layout

USBC Breakout Board available from Windfreak

4. Typical Performance

4.1 RF Output Power

The typical maximum and minimum output power of the SynthHD Mini is shown below. This graph is
of unleveled operation at the maximum and minimum RF power settings.

SynthHD Mini Power Range

Minimum and Maximum available Power

Power levels are settable in 0.01dBm increments via software. Onboard calibration is attained through a look-up table unique to each device. Device calibration is performed at the factory and stored in onboard flash memory.

SynthHD Mini Calibration Performance 10 MHz - 15 GHz

Typical Calibration Performance Graph

4.2 RF Output Harmonic Content

The typical SynthHD Mini harmonic distortion is shown below. This data is taken at a leveled fundamental power of 10dBm. If lower harmonic levels are needed, Windfreak Technologies suggest the use of low-cost SMA filters from Crystek and Minicircuits.

Example: Crystek Lowpass Filter – many cutoff frequencies, 1GHz example: CLPFL-1000, $25

SynthHD Mini Harmonics with 10dBm Fundamental Power

Typical Harmonics with 10dBm Output Power

4.3 Integer Boundary Spurs

A mechanism for in-band fractional spur creation in all fractional PLL’s is the interactions between the RF VCO frequency and the internal 27MHz reference frequency. When these frequencies are not integer related, spur sidebands appear on the VCO output spectrum at an offset frequency that corresponds to the difference in frequency between an integer multiple of the reference and the VCO frequency. These spurs are attenuated when outside the loop filter which is roughly 50KHz wide.

Example if using the SynthHD Mini 27MHz internal reference: For the fundamental VCO range of 7500MHz to 15000MHz the first integer boundary happens at 27MHz X 278 = 7506MHz, the next at 27MHz X 279 = 7533MHz and every 27MHz thereafter up to 15000MHz. Below the fundamental VCO band the spacing will be affected by the RF divider.

A typical case generating 7506.04MHz would give integer boundary spurs at a 40KHz offset at around 37dBc. A typical case generating 7506.40MHz would give integer boundary spurs at a 400KHz offset at around 58dBc. (These were measured with the reference doubler off and PLL ICP set at 5).

4.4 Phase Noise and Jitter

SynthHD Mini 250MHz Phase Noise

Phase Noise at 250MHz


SynthHD Mini 1GHz Phase Noise

Phase Noise at 1000MHz


SynthHD Mini 2.5GHz Phase Noise

Phase Noise at 2500MHz


SynthHD Mini 5GHz Phase Noise

Phase Noise at 5000MHz


SynthHD Mini 10GHz Phase Noise

Phase Noise at 10000MHz


SynthHD Mini 15GHz Phase Noise

Phase Noise at 15000MHz


5. Device Information

5.1 Mechanical Dimensions

SynthHD Mini Mechanical Dimensions
1.6” X 1.6” X 0.48” milled aluminum case


  • Wireless communications systems
  • RF and microwave radios
  • Software Defined Radio (SDR)
  • Radar
  • Automated test equipment (ATE)
  • EMC – radiated immunity pre-compliance testing
  • Electronic warfare (EW) and law enforcement
  • Quantum computing and device research
  • Plasma physics
  • Medical research and treatment


  1. Datasheet
  2. Quickstart Guide
  3. Software Users Guide
  4. Control Software GUI Download (hit Cancel during hardware search if demo-ing software)
  5. Linux & Windows Command Line Guide
  6. UART Hookup Guide for Arduino and Raspberry Pi
  7. Python Package