vna

A simple and cheap vector network analyzer, including support software.

As seen on kickstarter: https://www.kickstarter.com/projects/1759352588/xavna-a-full-featured-low-cost-two-port-vna

Directory layout

• libxavna: C & C++ library for accessing the hardware, see README.md in subdirectory for more info
• vna_qt: QT GUI
• pcb: schematics, pcb layouts, and simulation files
• vhdl: circuitry implemented on the fpga

Specifications

• Frequency range: guaranteed 137MHz - 2500MHz, typical 135MHz - 3500MHz
• Output signal level (configurable in software): -20dBm to 10dBm, with 1dB increments

Interfacing

• The main board connects to a PC through usb and communicates via a virtual serial port device; the PC software sets the frequency and other parameters by sending two-byte register write commands, and the device sends averaged vector values representing magnitude and phase of measured waves.

Table of Contents

• Downloads
• Building the software
• Pictures
• Screenshots
• Block diagram

Downloads

For pre-compiled executables go to: https://github.com/xaxaxa-dev/vna/releases

Building the software

Building on linux

Build libxavna (required for QT GUI):

sudo apt-get install automake libtool make g++ libeigen3-dev libfftw3-dev
cd /PATH/TO/vna
autoreconf --install
./configure
make
cd libxavna/xavna_mock_ui/
/PATH/TO/qmake
make

Build & run QT GUI:

sudo apt-get install libqt5charts5-dev
cd /PATH/TO/vna
cd vna_qt
/PATH/TO/qmake
make
export QT=/PATH/TO/QT # e.g. ~/qt/5.10.1/gcc_64
../run ./vna_qt

Building on mac os

brew install automake libtool make eigen fftw
cd /PATH/TO/vna
./deploy_macos.sh
# result is in ./vna_qt/vna_qt.app

Cross-compile for windows (from linux)

Download and build MXE:

cd ~/
git clone https://github.com/mxe/mxe.git
cd mxe
export QT_MXE_ARCH=386
make qt5 qtcharts cc eigen fftw pthreads

Edit mxe/settings.mk and add i686-w64-mingw32.shared to MXE_TARGETS.

Build

cd /PATH/TO/vna
export PATH="/PATH/TO/MXE/usr/bin:$PATH"
./deploy_windows.sh

Pictures

Main board (release 2)

Calibration standards (Short, Open, Load)

Screenshots

Open circuited coax stub

Antenna

Time to fault (measuring coax cable)

Block diagram

Overall architecture

Receivers & interfacing

Signal generator

FPGA logic

Parts selection

T/R version

• fpga: XC6SLX9-2TQG144C
• adc: AD9200
• mixer: AD8342
• synthesizers: ADF4350
• rf switches: BGS14GA14
• programmable attenuator: PE4312

Full two port version

• fpga: XC6SLX9-2TQG144C
• adc: ADC10080
• adc driver: ADA4932-1
• mixer: AD8342
• synthesizers: ADF4351
• rf switches: RFSW6024, BGS12PL6
• programmable attenuator: PE4312