https://devzone.nordicsemi.com/f/nordic-q-a/16820/nrf51822-bal-nrf02d3-flex-pcb-monopole-antennaHi, I&#39;m designing a 2 layer flex PCB with the nRF51822-CFAC WLCSP package and recommended ST BAL-NRF02D3 balun and i have chosen mono-pole antenna is a good choice,because i have enough room for it on PCB and they are cheap, easy to tune and possiblyen-USTelligent Community 13Tue, 04 Oct 2016 08:52:47 GMThttps://devzone.nordicsemi.com/thread/64366?ContentTypeID=1Tue, 04 Oct 2016 08:52:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:93c881a4-c201-421d-9f31-f2c11c4413efFormerMember<p><strong>1)</strong> To find an approximate length of the antenna you need to calculate the wavelength in the flexprint material. When you know the wavelength, divide it by 4 (quarter-wavelength antenna).</p> <p><strong>2)</strong> An antenna trace width of 1.5 mm works fine in FR-4 substrate, so I will assume it works fine on flexprint as well.</p> <p><strong>3)</strong> Yes, the length of the antenna is measured from the edge of the ground plane.</p><div style="clear:both;"></div>