[SOLVED] Dielectric constant and loss tangent of HP photo paper

hi,
I want to inkjet print by conductive ink on HP photo paper (which is commercially available for printing photos). Does anybody know the dielectric constant and loss tangent of photopaper?

I would be tempted to use viewgraph plastic sheets instead of paper:

Inkjet Transparencies - Transparencies

Being clear plastic, instead of some mash of wood particles, I would assume the dielectric constant would be much more repeatable. Of course, you would have trouble soldering anything to them!

by all means, let us know how it works out!

Hi
are you having access to Vector Network Analyser.. kindly check this link http://www.home.agilent.com/upload/cmc_upload/All/GTL91.pdf?&cc=IN&lc=eng
Idea is draw the microstrip line of known width and length, Measure scattering parameters with VNA. Then dielectric constant could be found.
One more paper is with me, which describes using VNA for measuring dielectric constants, if you wish, i can send..

Techi said:

Does anybody know the dielectric constant and loss tangent of photopaper?

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I would be tempted to use viewgraph plastic sheets instead of paper:

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Indeed. For that plastic sheet the dielectric constant would probably be 2.5 - 3.5 ... -ish.

Plus for a transparancy you can also use your favorite optical measurement methods to get an estimate of the dielectric constant.

hi biff44, I have to use paper substrate its mandatory, sure I will share the experience.

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vinoth8051 said:

Hi
are you having access to Vector Network Analyser.. kindly check this link http://www.home.agilent.com/upload/cmc_upload/All/GTL91.pdf?&cc=IN&lc=eng
Idea is draw the microstrip line of known width and length, Measure scattering parameters with VNA. Then dielectric constant could be found.
One more paper is with me, which describes using VNA for measuring dielectric constants, if you wish, i can send..

Click to expand...

Hi vinoth8051,yes its interesting paper. please send me the other one you have.

I recently did a big paper company job and ended up knowing more about paper than I probably wanted to. I would recommend you possibly look into paper with a high linen content. It bends a lot better without the fibers breaking.

The table in the material science script from the university days has an entry for "paper":

1MHz: epsr=2.99 tand=380e-4
10GHz: epsr=2.62 tand=403e-4

volker_muehlhaus said:

The table in the material science script from the university days has an entry for "paper":

1MHz: epsr=2.99 tand=380e-4
10GHz: epsr=2.62 tand=403e-4

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I am using 3.2 at 1GHz. what u suggest.

notice that even small amounts of moisture in the paper can strongly affect the dielectric constant

BTW, what kind of silver ink you use (producer)? In our company we use an expensive Japanese printer for printing conductive tracks with resolution of 5um

luben111 said:

notice that even small amounts of moisture in the paper can strongly affect the dielectric constant

BTW, what kind of silver ink you use (producer)? In our company we use an expensive Japanese printer for printing conductive tracks with resolution of 5um

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I am planning to use ink from cabot. which ink you suggest?

This has got me thinking, could you print a real pcb with this ink? They apparently have printers where you can manually feed cardstock in one sheet at a time. If you bought some FR4 boards that had ground plane on one side, and only dielectric on the other, fed them in one sheet at a time, I wonder if you could print actual solderable top surface metal?

You would still need to worry about via holes, but it would be pretty good for prototype boards or antennas, anything where the chip components were not too small.

biff44 said:

This has got me thinking, could you print a real pcb with this ink? They apparently have printers where you can manually feed cardstock in one sheet at a time. If you bought some FR4 boards that had ground plane on one side, and only dielectric on the other, fed them in one sheet at a time, I wonder if you could print actual solderable top surface metal?

You would still need to worry about via holes, but it would be pretty good for prototype boards or antennas, anything where the chip components were not too small.

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yes, we can print on one side of pcb board but as these inks are expensive so in case of PCB board milling or other etching methods are preferable.

A board costs at least $60, and it will take at least 2 days to get from a shop!

A router like LPKF is on the order of $15K to get going. And you have to buy router bits at some expense, as they wear down/break.

Just how expensive would the ink be for a 4 x 6" board with some microwave circuits on it (i.e. not many traces)? Even if it was $100 in ink, that would be acceptable.

biff44 said:

A board costs at least $60, and it will take at least 2 days to get from a shop!

A router like LPKF is on the order of $15K to get going. And you have to buy router bits at some expense, as they wear down/break.

Just how expensive would the ink be for a 4 x 6" board with some microwave circuits on it (i.e. not many traces)? Even if it was $100 in ink, that would be acceptable.

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yes you are right in saying if you have machines for both cases. Why are you not putting the cost of printer in case of inkjet printing?

In our company we use LPKF router for PCB prototyping plus we have proper chemical hole metalization. In just 6 hours you can get totally finished (no solder mask) PCB with up to 6-7 mils tracks. Now the dark sides - the router is really quite expensive, the chemical metalization also takes a lot of money, if you add the salary for the person who is hanging around the machine you'll find out that the price of single PCB is really very high.

There are many companies in Europe which can deliever your PCB in 2-3 days and even after 24 hours so you have to calculate how much will be the loading of the router before you buy it. From LPKF they told us that is very rare somebody to return the router (you have this option), usually they buy a second one.

I just read the Cabot spec of the ink and I totally changed my opinion - Cabot ink could be really soldered (in special conditions)! So if you use some low temperature soldering paste you can produce real PCB. The trick behind Cabot inks is that after temperature curing the ink particles which have low melting and sintering temeperature form solid metal layer!

From this view point the best material for printing PCB should be considered the Capton - I even see in the Cabot data sheet sample printed on Capton (you can tell the Capton by its yellow color). Of course photo printing paper is also acceptable, the only one problem is that it has on the top a layer of absorbing material - it can absorb moisture.

hi luben111, thanks for your opinion and I agree to it. I wish you could give some more details about photopaper.

Hi
Actually when you say "photopaper" you should not think about ordinary paper for newspapres or books. It's strongly laminated and it has plastics inside. From this view point it's acceptable for your goals because it absorbs less moisture. I guess the dielectric cosntant is between 2.5 and 3.5.

What worries me is the top layer of the photo paper which is strongly absorbing ink (and unfortunately moisture). I saw in the Cabot specs that the ink has excellent adhession to FR4 and PET, so you can try to print over some films for laser printing which widstand up to 250 degrees (ordinary PET is not OK because when heating it will simply melt). Otherwise I don't see any problem to use the photo paper - it will allow you to print thinner tracks compared to PET or Capton.

Thank you for the idea about this ink - it's extremely useful!

luben111 said:

Hi
Actually when you say "photopaper" you should not think about ordinary paper for newspapres or books. It's strongly laminated and it has plastics inside. From this view point it's acceptable for your goals because it absorbs less moisture. I guess the dielectric cosntant is between 2.5 and 3.5................

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hi, ya its a nice informative discussion. I will use dielectric constant from 3.0 - 3.5 and what you suggest the loss tangent at 1Ghz.

if you really want to make something professional I would suggest you try to print on Capton film. It can surfive high temeparture (>300 degC), it has excellent insulation properties and I'm sure it can work on frequencies above 1GHz.

One other possibility is to slightly remake the printer so it can accept directly FR4 PCB 1 or 1.5mm or ceramic plates. I think that small efforts in mechanical modifying of the printer can turn it into small PCB "factory". Theoretically the printer can't tell on what it's printing - paper of FR4 PCB but the mechanic was designed for paper.

Hi Techi, you may find the attached paper useful. It reports the dielectric constant and loss tangent of photopaper. Note that the reported values are functions of the curing conditions (heating the paper in oven after inkjet printing).
Shaker, G.; Safavi-Naeini, S.; Sangary, N.; Tentzeris, M. M.; , "Inkjet Printing of Ultra-Wideband (UWB) Antennas on Paper-Based substrates," Antennas and Wireless Propagation Letters, IEEE , vol.PP, no.99, pp.1, 0
Hope it helps.