I have tested the overload protection performance of the Ariel RF Limiter and it does what it says on the tin. Producing the specified limited +4dBm output power when driven by +30dBm (1W). The response is excellent to the specified 3GHz and the limiter continues to limit the input signal all the way to 7.5GHz. This units design is optimised for use up to 3GHz and so it lacks the elements needed for the demanding higher microwave frequencies. Such higher frequency microwave limiters are normally quite narrow band in nature and so not suitable for Ariel's application.
Ariel has very kindly sent me an un-built limiter and a filter PCB to experiment with. These items are not normally available to buy, but if enough interest is shown maybe Ariel will consider selling experimentation kits as well as built modules.
The case used for the limiter modules is very neat indeed and perfect dimensions for experiments in the microwave frequencies, as it is terminated in SMA connectors and very compact. Perfect for small RF PCB's.
The module case offers the RF experimenter many neat options of which I list a few below:
1. RF Limiter with user selectable attenuation and limiter diodes. The PCB is already designed by Ariel.
2. RF Filters. Low Pass, High Pass or Band Pass. Ariel has sent me a universal PCB for such use.
3. RF Notch Filters.
4. RF Fuse protection for Attenuators.
5. Power Inserter (BIAS 'T') for powering electronics via the coaxial cable.
6. Custom RF amplifiers using MMIC technology or discrete FET/Bipolar technology.
7. DC Block to protect equipment from DC offsets.
8. RF Matching transformer or Pad to change coaxial impedance from say 50 Ohms to 75 Ohms.
9. Static Dissipator to protect equipment from static electricity. (60V Gas Discharge Tube plus non inductive 2K2 resistor)
10. Custom Attenuator Pad.
11. Pocket Noise source (Biased Zener or genuine Noise diode feeding MMIC amplifier).
12. RF Detector probe head containing a microwave Diode.
13. FET high impedance converter for 50 Ohm equipment. 1M Ohm to 50 Ohms.
14. EMC E & H field probe head electronics modules with selectable probe sensors
15. Microwave SWR bridge
16. Microwave diode power sensor
And there are likely many more uses. I have often hunted for such a small and neat RF module case but most are designed for larger connectors and are unsuitable due to dimensions.
I like the fact that Ariel has used a 3D printer to create a build JIG that assures correct spacing and alignment of the SMA connectors during PCB assembly. He was kind enough to include the alignment JIG with my module parts.
We will have to see what Ariel decides to release in the future as accessories for his superb RF Explorer but he may also have a customer base for experimentation kits like that which he has kindly given to me. This Gentlemen is worth supporting. http://micro.arocholl.com/index.php?option=com_content&view=article&id=48:introducing-rf-explorer&catid=40:article&Itemid=64
I have deliberately not photographed the details of the Ariel's PCB's to protect his IPR.