Compact and High-Order On-Chip Wideband Bandpass Filters on Multimode Resonator in Integrated Passive Device Technology
Yun‐Peng Lyu, Yujin Zhou, Lei Zhu, Chonghu Cheng
Abstract
In this letter, compact, high order on- chip wideband bandpass filters (BPFs) are proposed in the gallium arsenide (GaAs)-based integrated passive device (IPD) technology. The design employs a stepped- impedance multimode resonator and achieves a bandwidth of more than five octaves with a high rejection to fourth/ fifth-order of the passband. A very small chip size is realized by implementing Metal-Insulator-Metal (MIM) capacitors and spiral inductors. Meanwhile, the equivalent circuit models and design equations are presented. A fabricated fourth-order prototype showed a low insertion loss of 1.2 dB, a 3-dB fractional bandwidth of 143%, and a upper stopband attenuation of more than 44 dB extending to higher than 30 GHz ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$> 10~{f}_{{0}}$ </tex-math></inline-formula> ). The filter size is 2.16 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 0.90 mm, which is only about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.02\lambda _{{0}} \times 0.01\lambda _{{0}}$ </tex-math></inline-formula> at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{{0}} =3$ </tex-math></inline-formula> GHz. To our knowledge, this is the widest BPF with the smallest circuit size ever published.