Siretta embedded antennas siretta echo1801muflss15 the siretta echo 18 is a wifi wlan dedicated pcb antenna that achieves impressive levels of performance due to fine tuning between 24 and 25ghz being tuned to this frequency band means the echo 18 antenna can be used with wifi bluetooth zigbee and ism based applications its miniature footprint size of only 37 x 6mm makes this sirettas smallest embedded wifi antenna it is therefore perfect for applications where internal space