Here are the Gerbers, attached.
Looks like file attach not working, look in programs folder, cypress, and you will
see the BLE kit folder
C:\Program Files (x86)\Cypress\CY8CKIT-042-BLE Kit\1.0\Hardware\BLE Pioneer Board
I have a doubt in AN91445 figure15. In 62mils L-leg says 215Mils. But acording to figure 10, maximum is 170mils. What is wrong in my understanding?
I am also confused about antenna and matching network design. Wherever you look there seems to be different designs. The size of the antenna in the design guide does not match the sizes in various example designs, which are all different. Furthermore the matching components vary. The BLE Mouse RDK uses 2 capacitors and an inductor. The BLE Remote RDK uses three capacitors and an inductor. PRoC BLE module for the pioneer kit uses one capacitor and one inductor. Datasheet specifies two capacitors and one inductor.
Also the antenna design guide makes no mention of 4 layer boards. Looking at the Gerbers for the Dongle for example, the top layer and the ground layer basically follow the design guide which has a cut-out in the ground layer. But the bottom layer which is also ground, does not have the cutout. Furthermore does "board thickness" mean the distance between the top layer and ground plane or the actual board thickness when a 4-layer board is used?
Layout, size of traces, sandwich thickness, loading, geometry of
traces to antenna, all factors that result in different antenna optimi-
zations. Also filters for harmonic suppression, FCC requirements, vary
due to a myriad of factors. This is RF, a bit of an art in practice. So
you will see variations. Motorola / Freescale many good ap notes on
RF practices, same for ARRL.
There are simulators for pc layout, geometry, stripline design.
I would follow the ap note as that relates directly to the output matching
of the Tx design for proper power delivery to the antenna.
You have to add pics as a file attach, yes we can see them, they then disappear into a
forum software black hole.
Ander454: Here is the design guide it covers the issue really well. Antenna and strip line design is a very cut and try process that requires very expensive equipment to debug and tune the design. You can make a design that works but will not be perfect due to variances in the fiberglass process and trace width changes due to over or under etching of the traces.
Ander454: I have even used epoxy to tune the balun feed connection by adding more or less of it on the antenna feed connection. We also purchased our blank fiberglass from only vendors that meet our testing requirements. I am surprised that the don't use a spiral antenna for this application or helix design. I realize that they are looking for broad coverage so I guess that they are using a dipole for this reason. But it I wanted to cover a large distance. I would be looking at a Yagi or spiral antenna. His is a high frequency and is affected by the smallest things in the design of the antenna circuit.
Aitor (and others). Having looked at the Gerbers that Cypress supplies for the MIFA antenna, specifically for an FR4, 2-layer, 62 mil-thick PCB, the size of the L-Tip (no that's not a typo) is 165 mils, I used this for my Diptrace footprint design for this antenna. I am guessing that Table 3 on page 13 is wrong but I hope we can get clarification from Cypress before I have boards made.
Yes there is definitely something wrong here. The gerber files follow the diagram on page 9 which doesnt specify a board thickness but according to the distance "W" and table 2, this is a 1.6mm board. But the L-Tip is wrong and doesnt match any of the reference designs or table 3.
The HID Mouse RDK uses a double-sided board of 1.6mm and the L-Leg measurement is 40 mil.
The table 3 specification of 215 mils for this would extend above the rest of the traces.
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I filed a case
[UPDATE] I have a reply to my case saying...
The information provided in the table is correct. The Gerbers files with the app note has some wrong information. We are in the process of changing the app note to correct this information.
Thanks for the update, although the information in the table, which they say is correct, doesnt match the "real" PCBs of the Mouse or remote RDKs. Lets see what they come up with.
I just heard back from Cypress about the case I raised; the value of L_tip in the table is a typo. It should be 115 mils, not 215 mils. Corrected documentation is coming they say.
I updated my PCB footprint design in Diptrace and it now looks like the PSoC 4 BLE module antenna.
I also raised a case on this a couple of days ago, specifically querying this dimension so looks like they replied to both of us. This confirms the supplied gerber files in the app note are also incorrect which I have pointed out in a reply. Note this is an "L-Leg" length rather than "L-Tip".
Does anyone know if all those masses of vias are really necessary? The PCB manufacturers are going to think I have gone insane with that many holes to drill, and thats not good design practice. I might stick with one row along the edge of the ground plane as shown in the diagram in the app note rather than a whole matrix of them.
Andy, not sure we got the same information - I am under the understanding that the only error in the App Note was the 215 mils number should be 115 mils but I agree that would make the supplied Gerbers wrong. Can we compare notes? Email me at ted @ mbelectronicdesign.com ?
Those vias are necessary IMHO