Technical FAQs

Marki can currently support all the current production parts that Precision has designed and built to date.

No, Marki has purchased the Waveguide business of Precision. This includes www.precisionmmw.com which will host all of the product portfolio options until such time that they can be integrated onto www.markimicrowave.com

Marki will expand the waveguide offerings based on its developing portfolio strategy. For specific product requests, please contact [email protected].

While our current portfolio will support up to 220GHz, new products will be able support into the sub-THz frequency range.

Please go to https://www.markimicrowave.com/company/rfq/ to complete a custom product enquiry and our support team will be in contact with you.

This is a very good question. You have a sophisticated setup for calibrating out the LO feedthrough and sideband suppression.

First the phase deviation with IF frequency. The phase will always vary more with higher IFs than with lower IFs, simply because the same time delay becomes a greater phase delay at high frequencies. For example, a 5 degree phase shift at 100 MHz becomes a 50 degree phase shift at 1000 MHz since the period is 10 times shorter. We always test with a hybrid around 60 MHz.

Second, the unit variation. The IQ-0307LXP, as with any part number that begins with ‘IQ’ (as opposed to  ‘MMIQ’), is a legacy hybrid, hand-built mixer. As such it has inherent unit to unit and lot to lot variation. The performance can and will change depending on the circuit lot, diode lot, assembler building the part, and whether that assembler is having a great day or only an okay day. These are low volume products as well, so it is difficult to specify them precisely. Additionally phase balance is a difficult thing measure, so we typically do not measure it in production. This is why the only specs that we guarantee are uncompensated image rejection and LO-RF isolation. Since the image rejection is a combination of phase and amplitude balance, it is possible that the phase could be significantly different from the typical phase, and we might not notice in production. This is the second time recently someone has mentioned the phase balance of the legacy IQ mixers, so we plan to investigate it more carefully. However, if we cannot quickly find a root cause for the problem then we will only be able to change the typical number on the datasheet.

The long term solution for this problem is to use a much more repeatable MMIQ mixer. For your frequency plan I recommend the MMIQ-0520LS.

The ADM-0126 will begin to saturate around +5 dBm input power, and will saturate completely with +10 to +15 dBm input power. This is where you should see the best T3 performance.

The saturated output power is not affected by the negative bias, so whatever value is on the curve in the datasheet should be representative.

The noise figure, however, is high at these low frequencies, around 8 dB or so.

We currently recommend using ADM-0026-5929SM or ADM-0012-5931SM.

It depends on the type of mixer you are using. Usually, increasing the LO by a few dB can result in a slight, few dB, improvement in the 1 dB compression. However, further increase in the LO level tends to result in increasingly unpredictable mixer behavior and the 1 dB compression will not be increased further. This trend would certainly be the case for any standard double or triple balanced mixer available on the market today…with one exception! The Marki Microwave T3 mixer family, to our knowledge, is the only mixer available in the world whose 1 dB compression point actually improves with LO drive over a huge range of LO drive. A simple rule of thumb for the T3 mixer line is that the 1 dB compression point is equal to the LO drive minus 4 dB. Therefore, a T3 mixer with a +15 dBm drive will have a +11 dBm compression point. If that same mixer has an LO drive of +22 dBm, the 1 dB compression point will improve to about +18 dBm. The combination of the T3 mixer’s ability to increase its 1 dB compression point with LO drive and its ability to suppression intermodulation distortion makes it one of the most sophisticated and versatile mixers in the world!

Marki Microwave mixers and other devices are available with any combination of female and male connectors (all female connectors are the default catalog configuration unless otherwise specified on the data sheet).  Dash number designators for catalog models are shown below.

SMA connectors are compatible with SMA, WSMA, 3.5 mm, and 2.92 mm. Marki Microwave SMA connectors are useable to 40 GHz. For catalog products, SMA connectors are specified only for ports that function below 26.5 GHz. SMA connectors are durable, suitable for laboratory use.

2.92 mm connectors are compatible with SMA, WSMA, and 3.5 mm connectors. Mode free to 40 GHz, these connectors are useable to 50 GHz. 2.92 mm connectors need to be carefully aligned to avoid damaging the female receptacle. This makes them less suitable for laboratory use.

2.40 mm connectors are compatible with 1.85 mm V-Connectors. Mode free to 50 GHz, these connectors are useable to 65 GHz. The extended mating contact of the 2.40 mm connector is much less susceptible to alignment damage than the 2.92 mm connector, making the 2.40 mm connector more suitable for laboratory use above 26.5 GHz.

In our understanding, AM-PM conversion occurs as nonlinear devices saturate. This is why limiters in particular are not a good idea in low phase noise paths, and is also why amplifiers tend to have a bit of a sweet spot just above P1dB. However, this is a really deep question that will involve lots of experimentation over the coming years.
For now the safe advice is to design the chain to aim the input power at right about the compression point of each nonlinear device and try not to add too much extra nonlinear stuff if you don’t need it. It’s basically the balance of “Power good” and “AM-PM conversion bad”.