Archive for the ‘Magus fun’ Category

Folded Dipole – bent and twisted…

Wednesday, October 7th, 2015

Antenna Magus simplifies the task of choosing a suitable antenna. Of course if you simply need a structure that will radiate at a certain frequency – without a specific pattern or impedance requirement – the task is a lot simpler!

I have seen a number of articles and papers where the possibility of using logos as antennas is considered – most notably Apple in the iPhone and Macbook following the 2010 “Antennagate”  scandal. Designing a ‘logo-antenna’ seems quite straight-forward:

1.  Figure out how big the structure should be
2.  Figure out how to excite the structure

… and then see if it radiates efficiently.

How do you go about doing this for a general logo though? If you can start from a well-known antenna that has a similar structure or shape to the logo then (even without extensive EM and antenna knowledge) the principles and guidelines of  the known radiating structure can probably be used as a good starting point to determine how to achieve some form of semi-efficient radiation for the logo.


To illustrate, we have done a simple investigation using the official Magus logo. The “known” Folded dipole antenna can be morphed into a structure resembling the Antenna Magus logo… essentially a bent and twisted folded dipole. Starting from the Folded dipole designed at 1 GHz (courtesy of Antenna Magus) the “logo-antenna” above was designed.


And how does this “logo-antenna” perform… quite well! At the 1 GHz centre frequency, the reflection and radiation performance is comparable to the original Folded dipole, with a 14% (-10 dB) reflection bandwidth and a gain of 2.3 dBi at the centre frequency. Nice!

And what about other well known logos?

Some are easy:

While some of the best known logos such as Nike, Coca-Cola and Ford are not that easy to match up… any ideas?

Antenna Magus coffee art

Monday, 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

Birds eye view of Magus offices taken by 2 cameras mounted on an L-39 Albatros model aircraft

Tuesday, October 26th, 2010

One of my colleagues spend most of his spare time building gadgets from components that he imports directly from Hong Kong. He recently bought an L-39 Albatros 50mm EDF remote controlled aircraft and mounted two imported mini video cameras on the front and back of the aircraft to capture the front and rear facing views. He made a short movie (see below) of a bird?s eye video taken of our offices and surrounding area in Stellenbosch, South Africa.

I was very impressed by the quality so I asked him about the cameras. Apparently these mini cameras aren?t very expensive as they are basically reconfigured cell phones without the keypad and RF components and are mass produced in +- one million batches. The only drawback is that due to the nature of the cell phone industry the components change all the time so in 6 months one wouldn?t be able to get hold of those specific cameras any more.

Here’s the view taken from the ground, Note how fast the aircraft is moving!

Author: Robert Kellerman

Stairway to heaven

Thursday, September 16th, 2010

I?m not generally afraid of heights but after seeing this clip of an antenna technician climbing a 1768 foot tower, I much rather prefer designing antennas in my office than assembling them!

Amazing tower climb

Click here for an explanation where this video came from (and why the above Video link may stop working!)

Author: Robert Kellerman

Test your antenna knowledge

Thursday, June 17th, 2010
Antenna crossword puzzle

Antenna crossword puzzle

Someone in the office recently found a fun antenna cross word puzzle on and challenged all the antenna engineers to see who could solve it the fastest. I must say my memory was a bit rusty, but one of our engineers completed it in 11 minutes with only one mistake. Follow the link above and see if you can beat his time.

Author: Robert Kellerman

New Coffee espresso antenna

Thursday, April 1st, 2010
New coffee espresso antenna

New coffee espresso antenna

Who would ever imagine ground coffee could make an excellent dielectric? We recently did some research and experimented with different, cheaper dielectric materials.? One of our engineers suggested that we should investigate ground coffee. We originally thought it was a ridiculous idea but after some research on the electrical properties of coffee, we did a few simulations and surprisingly found that a standard double espresso group packed with ground coffee makes an excellent cavity and dielectric for a circular patch antenna in the 3.5 to 4.5 GHz range. The image above is a photo of the new Circular coffee espresso antenna. Note how conveniently the cable fits through one of the spouts.

We have been experimenting with different types of coffees and so far it seems like Arabica coffees with a lot of flavor (like the ones mentioned in my previous roasting coffee blog) give the best performance. The image below shows the new coffee antenna with a typical gain pattern at 4 GHz.

Look out for the new Coffee espresso antenna soon to be included in the Antenna Magus database!

Coffee antenna gain pattern

Coffee antenna gain pattern

Author: Robert Kellerman

Antenna towers ? ideal for base jumping

Friday, March 5th, 2010

Who would have thought that antennas and extreme sports have something in common? In the past two decades, base jumping has become more and more popular and apparently high antenna towers make excellent launch platforms. The sport evolved so that base jumpers can also wear special jumpsuits (or wingsuits) that shapes the human body into an airfoil which can create lift and allows them to travel horizontally at ridiculous speeds.

Base jumpers who live in the city far away from cliffs and mountains often have to make use of manmade structures to satisfy their need for an adrenalin rush. Usually jumping off buildings is illegal and jumpers mostly have to jump at night, facing the risk of being arrested. Since 2001 Kuala Lumpur launched an annual international event where jumpers from all over the world take part in jumping off the famous KL tower. This allows base jumpers to do several consecutive jumps during bright daylight with no police handcuffing them at their landing spots.

I?m wondering how many base jumpers become technicians (or maybe vice versa) who service antennas just to get access to ideal base jumping destinations? Has anyone taught them about ICNIRP compliance and the dangers of RF overexposure?

Free falling next to KL tower.

Free falling next to KL tower.

Author: Robert Kellerman

Google vs Magus

Tuesday, December 1st, 2009

Magus vs Google

How many of you can remember doing anything on the internet before Google? Google was founded by Larry Page and Sergey Brin and was first incorporated as a privately held company on September 4, 1998. That is only 11 years and two months ago! I cannot imagine using the internet without Google but there was a time when libraries were the only place where knowledge could be acquired.

I want to draw a few parallels between Google and Antenna Magus.

Google Antenna Magus
The first internet search engine of its kind. The first antenna design tool of its kind.
The easiest way to find information on the internet. The easiest way to find information on antennas.?
Founded by a small group of IT geeks. Founded by a small group of antenna geeks.
Has the largest database of information in the world Has the largest database of antenna designs in the world
Changed the way people use the internet Is?changing the way people design antennas

It took a couple of years before Google became well known and widely used. That applies to anything new ? people need to use it first to realize how much they like it and eventually realize they can?t live without it. Antenna Magus is still in the first phase where people are discovering how useful it is but there are already some users who are loving it!

Here is a quote from one of them:

Through Antenna Magus I’ve been exposed to a number of antennas that I knew nothing about! In addition Antenna Magus has given me a good feel for what they are good for, physical insight into how they work and perform, a grip on how to design them, and where to find the key references.

Author: Robert Kellerman