Alternatives to SMA connectors in multiple-channel RF applications

Question

I have a circuit with multiple input channels (~10-20), where to each channel I am applying RF voltage signals, usually sine waves, with varying frequency in the range of 1MHz to 1GHz and 0-5V peak-to-peak amplitude.

I am using SMA connectors to send the signals from my Arbitrary Waveform Generator (AWG), however, I am currently looking at creating my own PCB with transistor oscillators on it.

The problem I am facing is that SMA connectors are too bulky and require SMA cables to connect my Device Under Test (DUT) to my oscillator circuit. Moreover, they are a bit of an overkill for a circuit that only goes to ~1GHz.

My question is: Do you have any recommendations for multi-channel connectors that are preferably clip-on (no cables) and support the necessary bandwidth and voltage range? I have been looking at U.FL connectors for a while as they are inexpensive, but as far as I understand, the female connector is always on a cable and only male connectors exist as SMDs.

Answer 1

You didn't say so, but reading between the lines I seem to understand that you're looking for a board-to-board coaxial connector suitable for many mating cycles between a text fixture and devices being tested. You wish to make multiple connections at once, rather than one at a time.

If so:

Consider a set of compression coax connector: https://www.te.com/en/product-1658260-1.html

You would install a number of these compression coax connectors on the fixture. The DUT would have flush coaxial PCB pads in the corresponding locations. When you place a DUT on the test fixture, you press it against these connectors which would retract slightly as they apply pressure against the coaxial pads and make contact. The fixture would lock the DUT in place to retain the contacts. When the test is done, you would move to the next DUT.

Note that the cost of the connectors on the DUT is zero: pads are free.

{Source TE 1658260-1}

Answer 2

you're searching for a multi-ganged RF connector. They're available from a few vendors. Here's an example of one such product https://www.samtec.com/rf/cables/micro-ganged/ although similar products are available from other vendors. They're not cheap, but they would give you a PCB mount connector that would support an SMA at one end of a coax, and a smaller PCB connector on the other.

Answer 3

I recommend ZIF to FPC or micro-ribbon headers with interleaved pairs for Gnd isolation reducing crosstalk.

Add series R and terminate impedance to optimize results if unknown but 100 ohm single 200 ohm differential was common. A Gnd. foil shield will lower the common mode impedance more.

This then may be tested for signal integrity with various tests for crosstalk, Z, and pF per channel.