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RadioCAD antenna design

Over the last twenty years I have designed a number of production antennas; a lot of l/8 whip antennas (helical stubs), but also a nice selection of printed PCB antennas, slot antennas and wire-form antennas. If you need a custom antenna designed then contact me - there aren't many of us left in the UK now.

There follows some examples of my work:

868 MHz PCB antenna

868 MHz tiny, balanced PCB antenna showing mounting for a test balun

This tiny printed dipole had to give a reasonable gain and good omni-directionality at 868 MHz. The chip feeding it had a balanced input/output so the test PCB you see above had a test balun fitted for 50W testing.

 

Small whip antenna         868MHz whip prototype

Whip antenna prototypes

Winding a helical spring to give good antenna gain at lengths shorter than l/4 is not as easy as you might think. I found over years of trial and error that I could get down to l/8 before antenna performance fell off a cliff. Everyone always wants the antenna as small as possible!

 

Three dipole direction finding antenna         DF antenna under test

121.5 MHz direction finding antenna

This three dipole VHF antenna is used for direction finding on the aviation distress channel 121.5 MHz. I also designed the electronic receiver that measures the tiny differences in phase between the antenna elements and thereby determines direction to target.

 

UHF wideband log-periodic

UHF wideband log-periodic antenna

Here we have the prototype of a 470 to 864 MHz log periodic antenna designed to be printed onto a glass substrate and then bonded into a laminated glass product; an elegant internal TV antenna.

 

868 MHz directional antenna

868 MHz hi-gain directional antenna

This wire-form directional antenna gives a gain of 9 dBd (11 dBi) for a 60 3 dB beamwidth. I still have a test facility where I can measure antenna performance: azimuth, altitude, gain, antenna factor and return loss.

 

antenna measurements

Antenna measurements: gain-v-frequency, azimuth, return-loss

These are the gain-v-frequency, azimuth, return-loss measurements I made for the above wire-form antenna.

 

125KHz prototype loop antenna being tested

125KHz prototype loop antenna being tested

I have retained the equipment and test antennas to make measurements from 9 KHz to 8.3 GHz.

 

Tri-band 3G PCB antenna

Prototype Tri-band 3G PCB antenna

This tri-band 3G antenna was designed to fit in a very small space along the edge of an existing customer PCB.

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