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

Preview of newsletter 3.1

Preview of newsletter 3.1

Author: Robert Kellerman

The Magus board

June 9th, 2011

Magus board close-up

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

Front view of the Magus board


Back 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

FEKO model preview

Calculated gain pattern

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

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

Antenna Magus 3.0 released

April 20th, 2011

We are proud to announce the third major release of Antenna Magus, version 3.0!

Here’s a quote by Sam Clarke, our Managing Director:
“Soon after the first release of Antenna Magus we received numerous requests from customers who wanted to add their own antennas and designs to the Antenna Magus database. Having a tried and tested system that was already regularly used by our own engineers in developing content for our product, and having received valuable feedback from a group of selected users, we developed a way to store antenna information which makes sense to antenna engineers. We are confident that this feature will not only improve the way antenna information is managed but will become the norm for any organisation who wants to capture, reuse and share valuable knowledge efficiently.”

This calls for a celebration! Read more about Version 3.0 in Newsletter 3.0.

Here are two movies which highlight the “Add your own antenna” and new “Chart tracing tool” features:

Add your own antenna movie.

78 Second Chart tracing tool demo.

Author: Robert Kellerman

Have we reached the tip of the ice berg?

February 14th, 2011

iceberg

With almost 160 antennas in the Antenna Magus database we have heard people saying, ?Are you still planning on adding more antennas to Magus or do you think you?ve almost reached the tip of the ice berg?? and our response has always been, “we’re not even close”.

Recently one of our blog readers was looking for an antenna with about 10 dB gain in two opposite directions, for use in a tunnel (Narrow band). Even though there are so many antennas in Antenna Magus, the only bi-directional ones are the spirals. The spirals don?t have the gain, and require baluns, which add to manufacturing costs. Of course he could use an array, but this is going to be too big, and the feed network adds a lot of manufacturing complexity. This just proves that there are still more antennas that need to be included in our database!

I thought this is actually a nice opportunity for a challenge. Lets see if anyone can come up with a better (but simpler) type of antenna to achieve this (pattern below). Actually one of our antenna engineers came up with a great idea which I will share with you in an upcoming blog.

More or less the pattern he is looking for.

More or less the pattern he is looking for.

Author: Robert Kellerman

Antenna Magus Evaluation version corner reflector improves home internet reception by 12 dBi.

January 17th, 2011

900 MHz corner reflector designed in Antenna Magus

900 MHz corner reflector designed in Antenna Magus

I was quite chuffed when I saw this post on mybroadband about a corner reflector that was designed using the free Antenna Magus Evaluation version.

He explains how he designed and built a corner reflector from an old printer box and aluminium foil. It is used to boost the 900 MHz UMTS link between his home 3G modem and internet base station which increased the signal by 12.5 dB!

Obviously this will save a lot of money compared to commercial options which will cost over 150 US$ for a > 10 dB gain antenna and coupler which still has to be mounted on the roof (see http://www.poyntingdirect.co.za/c22/Antennas.aspx). I just don?t know how I will convince my wife that we have to place this beautiful foil covered box in the living room (coincidently the position of best reception).

Wife: ?Under no circumstances! Our internet works fine.?
Me: ?I know it is not an oil painting honey but this will greatly improve our internet speed?and we save 150 dollars!?

Author: Robert Kellerman

Antenna Magus version 2.4 released!

December 15th, 2010

We recently launched Antenna Magus 2.4.0. This update features 8 new antennas – 6 of which are dielectric-supported helical antenna variations. The other two antennas are the Sierpinski gasket antenna and a blade antenna. The Sierpinski gasket was a very popular antenna in the late 1990’s when fractal antennas were being widely researched, while the blade antenna family is one of the most frequently requested antennas in our communications with Antenna Magus users.

You can read more about this release in the latest Newsletter 2.4

Preview of newsletter 2.4

Preview of newsletter 2.4

Author: Robert Kellerman

Antenna Magus coffee art

December 6th, 2010

If you’ve been following my blog, then would have probably realised that we at Magus are very passionate about our coffee. We’re also passionate about antennas so we thought of a way to combine these two passions. I present to you…antenna coffee art! One of our engineers (who also earned his reputation as our local barista) taught himself how to make pictures pouring frothed milk onto an espresso. Here’s a 90 second movie of some beautiful antenna patterns he created.

Author: Robert Kellerman

Antenna made from salt water!

November 26th, 2010
Sea water antenna

Sea water antenna

I love it when engineers think outside the box. When asked to design an antenna that can be mechanically adjusted for different frequencies most engineers would think of metal structures with some sort of adjustable length (like that ancient TV antenna which I blogged about some months ago). But who would think of making an antenna from salt water? When someone told me about it my first reaction was, no ways, this is probably some joke or something, but it’s not. Follow this link or watch the video clip below for a detailed explanation. The principle is quite simple – a salt water fountain with variable height acts as the resonant structure and a magnetic current probe picks up the induced fields from the water stream positioned in the center of the probe which is connected to a receiver.

I’m sure we’re going to see more of these salt water fountain antennas in the future. Can I have one for my iphone please!

Author: Robert Kellerman

The isotropic radiator

November 18th, 2010

head

I wonder how many engineers fully understand the term “isotropic radiator”. We recently had an interesting discussion about this. What is really interesting is the fact that although an isotropic radiator cannot exist in practice, it is used in so many antenna synthesis and theoretical applications that one commonly finds the term used as if such a device does in fact exist in reality!

In order to clear up any confusion around isotropic radiators, we need to first make sure about the definition of the term “isotropic radiator” (some people – even university lecturers and highly regarded academia – confuse this term with “omnidirectional radiator”). The IEEE standard defines these two terms quite clearly as:

Isotropic radiator, A hypothetical, lossless antenna having equal radiation intensity in all directions.
Note: An isotropic radiator represents a convenient reference for expressing the directive properties of actual antennas.

Omnidirectional antenna, An antenna having an essentially non-directional pattern in a given plane of the antenna and a directional pattern in any orthogonal plane.

Few if not none, antenna textbooks explain why an isotropic antenna is theoretically impossible. However Silver gave a simple proof more than six decades ago (S. Silver (Ed), Microwave antenna theory and design, MIT Rad Lab Series, McGraw-Hill, 1949, pp 78-79). Subsequently, in 1954, Mathis offers a more complicated proof after invoking an obscure mathematical theorem of Brouwer, 1909.

Isotropic radiators are commonly used in array synthesis to determine the antenna factor which is then multiplied by the vector field of the single element in an array to synthesise the array pattern.

I remember how I once spent quite a lot of time struggling to analyze an array of radiators in a full-3D EM simulation tool to determine the array factor of a base station antenna. The array patterns in my simulations all showed a ?glitch? (extremely high field value) in a specific direction and only after lots of investigation and ?debugging? I realized that the field vector orientation in the isotropic element patterns that I was trying to use as array elements was undefined (or rather ambiguous) at the poles (theta = 0 and theta = 180).

The analogy used by an antenna engineer I know describes the problem quite well: ?The direction of field vectors at the poles of an isotropic radiator are undefined, just like the direction of the hairs at the crown of your head ? it?s just something one has to make a peace with!?.

Author: Robert Kellerman