Compact High Q Configurable Quint-Band Electromagnetic Bandgap Filter

A compact quint-band bandpass filter using an electromagnetic bandgap (EBG) material is proposed. To the best of authors' knowledge, this is the first quint-band filter using the EBG material. The quint-band EBG filter consists of EBG substrate and five sets of lumped capacitors. In comparison with other quint-band filters using stepped impedance resonator, the EBG filter has advantages including high Q, a wide stopband, and good band-to-band isolation. The employment of external capacitors makes it possible to control each passband's working frequency. This paper provides a simple and effective method to design a quint-band filter with a low insertion loss and a compact size. Experimental verification is provided, and a good agreement has been found between simulation and measurement. The measured return loss of the five passbands is better than 13.0 dB, and band-to-band isolation is better than 29.0 dB. The spurious signal suppression in the upper frequency range from 3.36 to 10.0 GHz is higher than 20.0 dB.