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

Abstract

A compact 60-GHz active receiving antenna array is designed and fabricated using low temperature co-fired ceramic (LTCC) technology. It integrates a 4 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,\times\,$</tex></formula> 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 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$({\rm SWR}&lt; 2)$</tex></formula> 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 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{\circ}$</tex> </formula> 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 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,\times\,$</tex></formula> 20 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,\times\,$</tex></formula> 1.4 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{3}$</tex></formula> , 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.