Integration of Circular Polarized Array and LNA in LTCC as a 60-GHz Active Receiving Antenna

A compact 60-GHz active receiving antenna array is designed and fabricated using low temperature co-fired ceramic (LTCC) technology. It integrates a 4
$\,\times\,$
4 circularly polarized (CP) patch array and a 21-dB low noise amplifier (LNA) into the same package substrate. By applying a stripline sequential rotation feeding scheme the CP array exhibits a wide impedance bandwidth
$({\rm SWR}< 2)$
and 3-dB axial ratio bandwidth, both over 8 GHz, as well as a beam-shaped pattern with a 3-dB beam width of 20
$^{\circ}$
and a peak gain of 16.8 dBi. By applying a bond wire compensation scheme and low-loss transition optimization, the LNA is successfully integrated into the package. The final fabricated prototype measures only 13
$\,\times\,$
20
$\,\times\,$
1.4 mm
$^{3}$
, demonstrates the good integration performance as well as the CP polarization characteristics in measurement, and is estimated to have a peak overall gain of at least 35 dBi.