文摘
In this article, a Ka-band narrowband multilayer bandpass filter (BPF) centered at 34.5 GHz is presented, where a hybrid structure of two substrate integrated waveguide (SIW) cavities with slots and CPW is used to meet the good filtering capability and compact size. Benefiting from the 3-D circuit layout, the proposed filter can effectively overcome a vital drawback of large circuit size of traditional filter, and be used in system-in-package application. The circuit size of the filter excluding feed lines is about 0.5λg by 0.5λg, where λg is the guided wavelength at the central frequency of 34.5GHz. Simulated results show that the filter has the 3dB bandwidth of 0.86 GHz (FBW = 2.5%) and insertion loss of 1.7 dB at central frequency.