Where to find dialectric substrate with EPsr=40 or EPsr=50?

[dghd]

microstrip antena

where can i find dialectric substrate with EPsr=40 or EPsr=50?

 

[Kit-the-great]

Usually it's a some sort of ceramic materials. Try:
www.murata.com
**broken link removed**

Or search the 'ceramic substrate' on the web.

Best regards,
Kit-the-great

 

[dowjones]

hello,
I read the topic and the question, and I wonder why do you need such high eps for an antenna?. If you make an antenna with that material it will not radiate!!.

One patch antenna with that ceramic material will act as a tuned resonator (for a filter or something like that)

regards

 

[zorro]

Hi,

hello,
I read the topic and the question, and I wonder why do you need such high eps for an antenna?. If you make an antenna with that material it will not radiate!!.

One patch antenna with that ceramic material will act as a tuned resonator (for a filter or something like that)

regards

It is true that the bandwidth of a patch antenna decreases with the increase of eps of the substrate (any patch antenna is a resonator).
But even with a very high eps it will be anyway a radiator, although its efficiency will be poor.
The are tradeoffs between size-bandwidth-efficiency. See the topic about small antennas in this forum.
Regards

Z

 

[eirp]

for microstrip patch antenna holds:

Simply written

Bandwith~(1/Radiation Q)~(epsr/h), h is substrate height

 

[hca41316]

I think you mean: Bandwith~(1/Radiation Q)~1/(epsr/h)

 

[dowjones]

Hi zorro,
Its true, it will radiate, as well as any structure will do (even a cable, if you dont mind the 80-90db shielding).

I think that an antenna is a device made to radiate as efficiently as posible. Therefore if you use a high eps (40 as dhgd mentions) you will have a tuned resonator with a high Q and very small bandwidth (a few kHz or even lower) and very poor radiation efficiency, probably lower than -10dBi. My suggestion to dghd is that he thinks of another tyoe of antenna (a dipole) if it fits into the available volume

regards