Frequently Asked Questions (FAQ)

Q: How do you connect multiple X-Microwave Block PCBs together?

The ground-signal-ground jumper (gsg Jumper). It is a small piece of Polymide material with copper traces that are shaped for 50 ohm impedance across the launch.
The copper traces are coated with diamond particles and then gold plated creating ‘diamond particle interconnect’.
The gsg Jumper is then laid across two boards and two Anchors are used to hold it firmly against the PCB on each side of the connection.
The connection has been validated to the limits of our current instrumentation 67 GHz and we anticipate good performance at higher frequencies.

Q: What if I don’t want to use the X-Microwave gsg Jumper?

Multiple approaches can be used to connect between boards.  They have an ENEPIG finish allowing them to be wire bonded, epoxied, or for ribbon to be soldered between the launches of two boards.
 

Q: What is the S-Parameter of the gsg Jumper… does it really work?

Yes it works, de-embedding it doesn’t really make sense.  However, you can compare two boards connected by a gsg Jumper to a single transmission line of the same length.
Performance comes out to fractions of dB difference in the measurement of a single 08 length board and two 04 boards in series connected by a gsgJumper.
The higher the frequency, the more important the placement, but overall it’s solid and is the closest thing we’ve seen to continuous PCB.
 

Q: Is the gsg Jumper hard to place?

With some practice placement can be close to as quick as establishing a good cable connection.  
It is small and steady hands are required. We have found the small end of a jewel picker works well. Any may work so long as it does not leave residue.
We typically use tweezers and a magnifying glass (or microscope) to inspect the connection.  On side is installed and then captured by an Anchor before the other side is anchored down. 
 

Q: What frequencies do you support?

The most common board and transmission line architecture in the system works well to 50GHz. 
We have added provisions for working to 60 GHz that are in production and have projects in the lab approaching 100 GHz.
Our objective is to make all of the blocks compatible allowing you to seamlessly design at all frequencies with the same system.
 

Q: What is the board stack up?

4 layers. Total stackup is 49 mil. The RF substrate is 8 mil Rogers 4003. We have been experimenting with many variations on this but keep the total height of the stackup and the launch the same to maintain compatibility between blocks.

Q: What if I need a part you don’t currently support?

We’re interested in working with you.  We support a range of options including designing it in and adding it to the catalog (at no NRE), creating custom designs, and even licensing some IP so that you can integrate it yourself.
 

Q: My design is completely prototyped. Can X-Microwave help with production?

Yes, absolutely.  The system was designed production ready. But for higher volume runs we like to combine the Gerber files from individual blocks into a single PCB.
We have several options either building the production units for you or licensing the design for your own manufacturing.
 

Q: Do you have S-Parameters and/or X-Parameter for X-Microwave blocks?

Yes, many blocks have a S-Parameter and X-Parameter data available. Each device is serialized and S-Parameters are taken before it ships.
As we have a chance we’ve been uploading that data online to the block’s web page where it is viewable in the interactive S-Parameter viewer.
X-Parameters from X-Microwave are available in Keysight’s Genesys software as a toolkit that installs with the software.

Q: Is the spring loaded pins included with the RF and/or Biasing boards? There is no pricing available on your website.

Spring pins are available installed with all control boards. To order the spring pin version please order the same part number with ‘-SP’ at the end. The cost of installed spring pins usually adds $15 – $20 to the price of the board.
For example XM-A2J9-0404D is a 5V Voltage Regulator. With spring pins the part number becomes XM-A2J9-0404D-SP.

Q: Will you be making a cheaper SMA version of the X-MWprobe?

We have evaluated many alternatives to the probe and we’re not seeing the performance out of surface mount connectors that meet our expectation. We’re currently offering MMPX connector on PCB 183 but it’s only good to around 30 GHz.
The SMA board is in the works but we’re still not happy with the results so we’ve been trying different shaped RF traces and ground planes. We don’t expect that any lower cost PCB based probe will have the RF performance, ease of use or robustness of the standard X-Microwave probe but we do understand the lower cost connection does have it’s place, for example, on the low frequency side of the mixer.
 

Q: Is the Interface Board included with the Prototype Station Kit?

Yes, the RaspberryPi interface board and feedthru capacitors for power signals are included with both prototyping kits i.e. XM-PSK2-08 (including a pelican case, prototyping plate, and probes) and individual prototyping stations i.e. XM-PB1-3232-01
 

Q: Do you get different types of interface boards?

Today there are 2 types of interface boards but the number is growing.
The standard interface for the 3232 (32 x 32 grid unit) plate has a 40 pin RasperryPi connector and room for 8 feedthru capacitors.
The standard interface for the 1616 (16 x 16 grid unit) plate only has feedthru capacitors.
 

Q: Is the biggest Prototype Plate is 32×32? Can you connect multiple of these plates together? And how do you connect these together?

When two prototyping plates are connected together, the grid continues seamlessly. To connect them we use two long wall pieces (XM-WT1-0601) on the bottom side of the prototyping plate. 
The 32×32 and 16×16 are the only two plate sizes we make today. (However custom enclosures can be produced of nearly any shape and size.)
 

Q: You use Rogers RO4003 for the RF boards. What do you use for higher frequency applications where these boards have too much losses (>18GHz)?

We have good success with RO4003 for the RF layer and find it to be suitable to 67 GHz. You can review the S-Parameter of our transmission lines to get a better idea of how the RO4003 performs.
 

Q: The Raspberry Pi Kit came with your software included on it. Can you use this software on a PC and where do you get it?

We offer the XM-RPK-01. It provides a stand-alone touch screen configuration for control of programmable X-Microwave blocks including switches, digital step Attenuator, PLL, MPAC, and more.  
When you order the kit it includes the stand-alone RaspberryPi based touch-screen hardware, pre-loaded with X-Microwave software, and 40pin ribbon cable.
 

Q: How are new parts added to the RaspberryPi Kit software? Where can the customer find these libraries for all the other parts?

We’re adding new parts mostly. The latest release of the X-MWcontroller software can be downloaded from our website and the PI can be updated with a usb drive.
See X-MWcontroller section of the the getting started documentation for more details.

Q: What are the costs to put together an CMA (Combined of X-Microwave Block Assembly) as an alternative to individual X-MWblocks and using the gsgJumper and Anchors?

CMA’s are a convenient and affordable way to develop production assemblies using X-Microwave blocks. In most cases a CMA can be designed and assembled no NRE.
The process consists of:

  1.  The customer specifies the X-MWblocks and the order of those blocks. This can be done using the layout tool (http://cascade.xmicrowave.com)
  2. Ideally individual X-MWblocks would be purchased, assembled, and tested to validate the design.
  3. X-Microwave can then quote the combined design.
    • Cost of populated PCB: Generally, the cost is estimated at the sum cost of all of the individual X-Microwave blocks (plus some additional panel fees if fewer than 10 PCB are purchased)
    • Cost of Test: Basic cascade analysis (usually S21) is included to 67 GHz
    • Volume discounts are available.
  4. X-Microwave will perform basic system level testing (usually a cascade analysis) and ship the CMA to the customer
  5.  Additional testing, packaging, and/or custom enclosure development is available.

Q: Can I purchase the Gerber/design files for X-Microwave blocks or CMA’s?

We can make X-Microwave based designs available in a variety of ways.

  1. X-Microwave manufactures the X-MWblocks or assemblies.
  2. X-Microwave licenses the Gerber file on a per module basis.*
  3. X-Microwave sells the Gerber file.*
    * Contact sales@www.xmicrowave.com for more additional information.