Bulk Acoustic Wave(BAW)filters find applications in radio frequency(RF)communication systems for Wi-Fi,3G,4G,and 5G networks.In the beyond-5G(potential 6G)era,high-frequency bands(>8 GHz)are expected to require res...Bulk Acoustic Wave(BAW)filters find applications in radio frequency(RF)communication systems for Wi-Fi,3G,4G,and 5G networks.In the beyond-5G(potential 6G)era,high-frequency bands(>8 GHz)are expected to require resonators with high-quality factor(Q)and electromechanical coupling(k_(t)^(2))to form filters with low insertion loss and high selectivity.However,both the Q and k_(t)^(2)of resonator devices formed in traditional uniform polarization piezoelectric films of aluminum nitride(AlN)and aluminum scandium nitride(AlScN)decrease when scaled beyond 8 GHz.In this work,we utilized 4-layer AlScN periodically poled piezoelectric films(P3F)to construct high-frequency(~17–18 GHz)resonators and filters.The resonator performance is studied over a range of device geometries,with the best resonator achieving a k_(t)^(2)of 11.8%and a Qp of 236.6 at the parallel resonance frequency(f_(p))of 17.9 GHz.These resulting figures-of-merit are(FoM_(1)=k_(t)^(2)Qp and FoM_(2)=f_(p)FoM_(1)×10^(-9))27.9 and 500,respectively.These and the k_(t)^(2)are significantly higher than previously reported AlN/AlScN-based resonators operating at similar frequencies.Fabricated 3-element and 6-element filters formed from these resonators demonstrated low insertion losses(IL)of 1.86 and 3.25 dB,and−3 dB bandwidths(BW)of 680 MHz(fractional BW of 3.9%)and 590 MHz(fractional BW of 3.3%)at a~17.4 GHz center frequency.The 3-element and 6-element filters achieved excellent linearity with in-band input third-order intercept point(IIP3)values of+36 and+40 dBm,respectively,which are significantly higher than previously reported acoustic filters operating at similar frequencies.展开更多
文摘Bulk Acoustic Wave(BAW)filters find applications in radio frequency(RF)communication systems for Wi-Fi,3G,4G,and 5G networks.In the beyond-5G(potential 6G)era,high-frequency bands(>8 GHz)are expected to require resonators with high-quality factor(Q)and electromechanical coupling(k_(t)^(2))to form filters with low insertion loss and high selectivity.However,both the Q and k_(t)^(2)of resonator devices formed in traditional uniform polarization piezoelectric films of aluminum nitride(AlN)and aluminum scandium nitride(AlScN)decrease when scaled beyond 8 GHz.In this work,we utilized 4-layer AlScN periodically poled piezoelectric films(P3F)to construct high-frequency(~17–18 GHz)resonators and filters.The resonator performance is studied over a range of device geometries,with the best resonator achieving a k_(t)^(2)of 11.8%and a Qp of 236.6 at the parallel resonance frequency(f_(p))of 17.9 GHz.These resulting figures-of-merit are(FoM_(1)=k_(t)^(2)Qp and FoM_(2)=f_(p)FoM_(1)×10^(-9))27.9 and 500,respectively.These and the k_(t)^(2)are significantly higher than previously reported AlN/AlScN-based resonators operating at similar frequencies.Fabricated 3-element and 6-element filters formed from these resonators demonstrated low insertion losses(IL)of 1.86 and 3.25 dB,and−3 dB bandwidths(BW)of 680 MHz(fractional BW of 3.9%)and 590 MHz(fractional BW of 3.3%)at a~17.4 GHz center frequency.The 3-element and 6-element filters achieved excellent linearity with in-band input third-order intercept point(IIP3)values of+36 and+40 dBm,respectively,which are significantly higher than previously reported acoustic filters operating at similar frequencies.
