Hi! In this video I will show how to use BetaMatch to calculate an optimized matching network for a multiband antenna
We will use an antenna called 'Dual Band' for this optimization.
The Touchstone data for this antenna is part of the demodata that comes with BetaMatch -
- and this is also the data that is loaded by default when BetaMatch first is started.
You can also always load this data from the 'Help menu'.
'Load Demo Data...' and select 'DualBand' and click OK.
Before we do any calculations we must get our reference plane right.
This is done in BetaMatch by setting the Electrical Delay.
Click on the text 'Electrical Delay' and enter the correct value in the box.
In this case it is 50ps.
Now we must also tell the optimizer which frequency bands we wish to optimize for.
In the 'Markers Menu' some of the more usual band configurations are predefined.
Here we will select 'Pentaband' which gives us the 850, 900, 1800, 1900 and 2000 MHz bands.
Notice that even if we have selected 5 bands we only have 2 distinct bands in our plots.
This is because the bands that we have selected are overlapping and BetaMatch will automatically merge them.
You can also see that the current frequency bands are shown in the status bar at the bottom of the window.
We should also make sure that we are using the correct component series.
This is done from the 'Components Menu', where we can select whatever component series we want.
The default selection is Murata 0402-sized components. Those are fine so we will not change them now.
Now we are ready to optimize. We can start the optimization either from the 'Toolbar' -
- or from the 'Optimize Menu' by selecting the topology we want and just click.
So, let us start by optimizing for a T-network.
There, it is done.
You can see the optimized network in the circuit diagram. Seen from the source it consists of a -
- series 3.9nH inductor a shunt capacitor of 1.6pF a series 2.7pF capacitor and the antenna.
We can compare the performance of this network with the design without any matching network.
Click on 'Original' to bring up the data for the unmatched antenna, and we can look at the Return Loss
The blue curve is the matched antenna and the black curve is the unmatched antenna. From the Return Loss we can see -
- that the matching now is much better at the lower end of the low band and the upper end of the high bands.
We can also look at the accepted power into the antenna,
- we can for instance see that it has improved from about 18% to 55% at the high band.
These results can also be viewed in tabular form in the 'Markers & Data window'.
Let me rearrange a little bit and expand the window. We can now see -
we have an increase from 18% to 55% accepted power at 2170MHz -
- and we have improved from 25% to 54% at 824Mhz.
Let us save this designed T-network into memory 1
These are the best results we could get with a T-network, -
- so now we wonder what would happen if we use more components, how much better would it be?
Well, let's find out. Let's start a 5 component optimization..
It will take maybe 35 seconds on this computer. It's a laptop with 2 core CPU around 2GHz clock.
not the latest model and not extremely fast. It is also slower because I am recording this.
The T-network before was almost immediate and 4 component optimization is also typically less than a second.
This 5 component optimization is considerably longer, but during this evaluation -
- the software is actually evaluating 186 million networks and picking the best one.
Now, it is done.
Now we have the best 5 component matching network and let us compare it to the best T-network -
- and also to the bare antenna without any matching network.
I will change the view a little bit so we can see both networks at the same time.
Turn ON memory 1. The red memory curve is the T-network and the blue curve is the 5 component matching network.
We can see from the accepted power that we have improved from 54% to 77% -
- and we have also improved from 55% to 66% efficiency at 2170MHz.
This is quite an improvement and even more so if we compare with the antenna without any matching network -
- which is black data in the plots.
At 824MHz we have improved form 25% to 77%.
At 2170MHz we have improved from 18% to 66%. Quite a significant improvement.
This shows the basic optimization, but BetaMatch also has some more advanced features
For instance it is possible to do Active Matching. The source can be changed to any complex impedance,
- and also the source impedance can vary with frequency.
Some other advanced features are:
Weighting: Target different efficiency for different frequency bands.
Pass- and reject bands: For instance to improve isolation between antennas.
It is also possible to match for 2 or 3 antenna sets at the same time.
For example if you have a flip- or slide-phone you can measure data in open and closed positions, -
- load the data into BetaMatch and match for both sets simultaneously.
That concludes this presentation. My name is Max Landaeus and the address to the web page and email is on the screen right now.
Feel free to contact me if you have any questions or other feedback. Thank you for your time and your attention.