xaVNA T/R and two port
The xaVNA is a two port VNA with a typical frequency range of 137MHz to 3.5GHz (accuracy specs guaranteed to 2.5GHz). It plugs directly into USB and requires no additional power supply. All measurements are done using an intuitive and easy to use UI on a computer.
It is both open source hardware and open source software, with a GitHub repository containing all schematics, PCB layouts, FPGA VHDL, and software:
As seen on kickstarter: https://www.kickstarter.com/projects/1759352588/xavna-a-full-featured-low-cost-two-port-vna/
What is a VNA useful for?
A VNA (Vector Network Analyzer) allows you to measure the impedance of an arbitrary device (such as an antenna) across a wide range of frequencies, as well as the transmission coefficient (gain/loss and phase) of a two port device (such as an amplifier, filter, or isolator).
Compared to an antenna analyzer, it gives you phase information as well, and lets you see the exact complex impedance of an antenna, allowing you to easily design matching networks without tedious trial and error tuning.
- Frequency range (guaranteed specs): 35MHz to 2.5GHz (since May 2019. 140MHz to 2.5GHz before)
- Frequency range (typical): 35MHz to 3.5GHz
- Signal level: -30dBm to 0dBm (S11 measurements up to -10dBm)
- S11 trace noise: < 0.1dB
- S11 dynamic range (calibrated): 50dB
- S21 dynamic range (calibrated):
- 70dB, f < 800MHz
- 50dB, f >= 800MHz
- Dimensions of the VNA board: 10cm x 10cm
- Weight: ~250g including enclosure
- Interface: Micro USB (cable not included)
- RF ports: SMA Female (cable not included)
- Current draw: ~800mA @ 5V
- Windows (7+), Linux, and Mac OS are supported
Software downloads available at: https://github.com/xaxaxa-dev/vna/releases
Screenshot (measuring antenna)
Accuracy comparison (measured vs simulated)