## Version 4.2 released

December 11th, 2012

We are very pleased to announce a new release of Antenna Magus Version 4.2. This release boasts 4 new antennas and an article about commonly used coaxial RF connectors which contains useful FEKO and CST MICROWAVE STUDIO simulation models of each connector.

As 2012 draws to a close we look back at an exciting year where Antenna Magus has become an integral part of the design process of more antenna engineers, assisting in making intelligent antenna design and modelling choices. 2013 is going to be an even more exciting year with lots of feature extensions and antenna additions planned.

Preview of RF connectors included in Antenna Magus.

Author: Robert Kellerman

## So how well does my antenna have to be matched?

October 26th, 2012

Friis equation illustration

Friis equation

I recently had some trouble matching an integrated antenna over the whole operating band, while sticking to the available space for mounting on a PCB? so? I got to wondering things like: ?what is the actual effect of return loss and gain on the communications range??

After spending some time musing about the Friis equation (above) – with the help of the Friis tool in Antenna Magus – I rediscovered why some general guidelines like ?- 10 dB is a good enough match and stick to lower frequencies for long distance communications?, are worth following.

I picked the following typical values:

Gt = Gr = 10 dBi, |S11|t = |S11|r = -20 dB, Pt = 1 W, Pr = 10 pW and Freq = 900 MHz.

and considered the effect of varying frequency, gain and |S11|t within this typical system. Note that the black marker on each graph represents the above-mentioned typical design case.

Relationship between return loss (|S11|) and range (R)

The above graph clearly shows why threshold for acceptable return loss is -10 dB. At -20 dB there is less than 2% reduction in range, at -10 dB and -6 dB the range is reduced to 5.5% and 14.5% respectively. In communication systems where maximal range is not such a strict specification 85.5% of the theoretical maximum range does seem like a reasonable trade-off, but if you can, it is definitely worth the effort to try get the extra meters!

Relationship between gain and range.

Next I plotted the relationship between antenna gain and range. The plot illustrates the communication engineers mantra: “for every 6 dBi increase in antenna gain, the range will double” – therefore range will increase from 80 km to over 2600 km when increasing the gain from 5 dBi to 40 dBi (equivalent to replacing a patch antenna with a large, high gain reflector antenna while changing nothing else in the system).

Relationship between frequency and range.

What about frequency? If we ignore all the pitfalls of propagation absorption and environmental effects, Frequency and Range are indirectly proportional to each other ? so doubling the frequency will halve the range. If one plots this relationship (as shown above) it is clear why long distance communication systems typically operate at lower frequencies.

So what did I learn from this exercise that helped me make some design choices?

1. I could increase my operating frequency so that I can use an electrically larger antenna that is easier to match. If, however, I need to increase the operating frequency by anything more than 10% to help me improve my reflection coefficient from -6 dB to -10 dB, the net result will be a reduction in range.
2. If I can design an antenna with similar size (and similar impedance), but with increased gain in the direction of interest, then I can achieve the same effect as improving the matching. The additional gain required in this instance is around 0.8 dB. For a low gain antenna like mine (with around 3 dBi gain) getting an additional 0.8 dB might be a challenge in the space I have. In another situation, optimising a higher gain antenna, like a 12 dBi horn – to get an extra 0.8 dB sounds a lot more doable.

I hope this exercise helped you (as it did me) put the different factors in a communication system in perspective.

Author: Robert Kellerman

## Version 4.1 released

September 19th, 2012

We are pleased to announce a new release of Antenna Magus – Version 4.1. This release sees the addition of 15 new tools, expanding the toolbox to 24 tools and calculators to assist antenna designers with every day antenna-related tasks. Tools include a chart-tracing tool used to convert trace data to numerical values, a two-port network parameter conversion tool, an RCS calculator, and a decibel (dB) to linear power ratio converter, among others.

For those who were not aware of this fact previously, Antenna Magus broke the 200 antenna barrier with the previous release and now boasts 204 antennas – the largest commercially available database of antenna designs in the world.

The Version 4.1 database is expanded through the addition of four exciting new antennas: the Axial choke horn with a dielectric lens, the Offset-fed Gregorian and Cassegrain reflectors and the ?Eggbeater? antenna.

Author: Robert Kellerman

## Models available for export to the AWR Design Environment ? (AWRDE) increased by 50% in 3.4

January 13th, 2012

We have received very positive feedback and growing interest from customers about the AWR model export capability, which was released in 2011. As with all the EM Analysis products supported by Antenna Magus (like FEKO and CST MICROWAVE STUDIO) the number of exportable models for these tools is continually growing. With the release of version 3.4, the number of models that can be exported to from Antenna Magus to AWRDE increased by 50%!

This functionality enables users to export models of antennas directly to AWRDE for analysis using the AXIEM solver. As with all Antenna Magus export models, the AWRDE models are fully parametric and validated across the entire design range. A number of the models use specially developed PCELLS to provide flexible geometries that can?t otherwise be created parametrically. These models can easily be integrated into circuitry and optimized together with other parts of the system.

More information on exactly which antennas can be exported to AWR can be found in the latest release notes.

Example of a capacitive disc fed patch which was exported from Antenna Magus to AWR?s Design Environment. The S-parameter simulations were performed in AWR's?Microwave Office? software.

Author: Robert Kellerman

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## Version 3.4 released

January 11th, 2012

During the development of a customer case study centered on the design of a Ka-band reflector antenna, the usefulness of exposing more of these design decisions to the user for parabolic reflectors became apparent. Version 3.4 is dedicated to releasing design algorithm extensions that do exactly that. There are 2 new parabolic reflector antennas, 2 new tools to aid in parabolic antenna design and 58 new objective groups added to existing parabolic reflector antennas. This added complexity makes the reflector class of antennas much more flexible, and will allow users to realise even better designs!

Author: Robert Kellerman

## Version 3.3 released

October 12th, 2011

We recently launched Antenna Magus 3.3. Antenna Magus Version 3.3 introduces some very exciting extensions to Antenna Magus.

• 6 new antenna topologies
• A new array distribution in the Array Tool
• 3 new tools added to the Toolbox
• Antenna Magus extended to include models for AWR Design Environment
• Many improvements to the Antennas and Models that are already available.able.

Author: Robert Kellerman

## Version 3.2 released

August 30th, 2011

We recently launched Antenna Magus 3.2. Antenna Magus 3.2 is the 16th product update since the release of Version 1.0. With a growing database of 159 antennas, 10 transitions and more handy calculators added to every release, the product has established itself as an essential tool in any antenna engineers’ toolbox.

Author: Robert Kellerman

## Antenna Magus 3.1 released

July 6th, 2011

We recently launched Antenna Magus 3.1. This update features 6 new antennas and 2 new transitions. More useful additions are: 3D gain patterns were added as part of the performance estimation, info docs now include summarising thumbnails which indicate the electrical size and typical radiation pattern of each antenna and the array synthesis tool undergone some major UI improvements. Read more in the latest newsletter 3.1

Author: Robert Kellerman

## The Magus board

June 9th, 2011

Magus board close-up

Someone showed me a message board which is similar to the one we use at Magus ? The panic status board. It?s a big board that shows the ?panic? status of the group. Emails that need to be followed up, number of days to the next major deadline, who is holding up development etc. The person who?s name appears at the top has the highest panic rating and is most probably the bottle neck. The person who?s name is never on the board is probably not working very hard at all so the best is to try and position yourself somewhere in the middle.

The focus of the Magus board is not to ?create panic? although from the info one can derive who has more on their plate. The other difference is that it does not require electricity, it works 100% mechanically!

One of our engineers came up with the idea after realising that (all though everyone?s work is already stored and tracked in JIRA) there was a need to show everyone what is happening with Antenna Magus – the current state of development; what is planned for future releases and what everyone is busy with. This would also invite different teams (like marketing who isn?t much involved in low level design) to give their input during early stages of development.

We bought a second hand free standing double sided notice board and modified it with wooden rails to hold small cards. We painted different horizontal colours which represent different stages of development and we hanged vertical dividers to separate different releases. Each card represents a different antenna or transition. It is printed on photo paper, each with a picture, title and a small sticker showing who is responsible for it.

Before an antenna or transition is chosen to be included in a specific release it is placed on the back of the board where its life cycle begins. Once it gets chosen it is moved to the front and placed in the appropriate vertical (release) and horizontal (development stage) positions. As work is done, it slowly progresses to the top of the board until it is ready for release. Once released the card is removed and archived.

I?ve seen lots of management ideas which try to involve various individuals but fail for various reasons. However this is not the case with the Magus board. It has lived through numerous releases and while writing this post I saw a few engineers moving their antennas cards and inspecting the board.

Front view of the Magus board

Back of the Magus board

Author: Robert Kellerman

## Blog follow up – Have we reached the tip of the ice berg?

May 25th, 2011

A while ago I blogged on finding a simple antenna solution for radiating down a tunnel in both directions and that one of our engineers already came up with the perfect solution. Interestingly enough one of our blog readers came up with exactly the same idea – a dual bore-sight horn. He actually created a FEKO model and calculated the gain patterns shown below. Our engineer replied, “I see? yeah, that is pretty much spot on, although I tweaked mine a bit to have a square flare and reduced length.” So he claimed that it can be improved.

FEKO model preview

Calculated gain pattern

However shortly after that one of our blog readers actually came up with an even simpler idea – a back-to-back axial mode helix using the same ground plane, fed by a power divider. The blog reader who originaly told us about his problem really liked that idea and decided to go for this option. The photo below is his first prototype and he is currently busy optimising his design for better performance and simpler manufacturing.

Back-to-back axial mode helix prototype

Thank you to everyone who responded with their ideas. In the end we could help our engineer friend to make an excellent choice!

Author: Robert Kellerman