loss tangent in microstrip antennas

Hi All,

As a part of my Masters project I have compare the frequency increase of multi resonant patches as compared to single patch. I found that by incresing the loss tangent of the dielelectric substrate I could increase the bandwidth (VSWR <= 2) of the multi resonant patches by significant amount, however the gain and efficiency decreased considerably, going even into negative for some values of frequency. Is such low value of gain and frequency acceptable for any application or there is some minimum desirable values for these parameters? If so, what is the min. limit on gain and efficiency?

Sincerely
mstripman

It's totally application specific. Maybe your system can handle low gain, maybe you need every 0.1dB you can get. Varies. E.g. if you are in a high signal strength environment you could get away with low gain, for instance HF wire antennas.

Matt

For cell phone applications, the most important factor is efficency...50% or higher is the standard...gain is not so important...a return loss of -6dB is acceptable.