A novel design method for small ultra-wideband(UWB)filter is proposed by using tortuously defected ground structure(DGS)to solve the problem of larger insertion loss and narrower stop band in the design of UWB filter. Firstly
a tortuous DGS is obtained by using winding shaped slot in the metal ground
and then equivalent circuit models are established according to the structural features of the parallel coupled-line and the transmission line of the tortuous DGS. The correctness of the circuit models is verified by using software HFSS
and the relation between DGS size and equivalent circuit parameters is deduced. The UWB characteristic of the parallel coupled-line and the low-pass/high selective characteristic of the transmission line of tortuous DGS are demonstrated. A simple and high-selective UWB filter is then designed based on the advantages of the two lines. Test results show that the insertion loss of the proposed filter is lower than those of the conventional DGS and the CRLH UWB filters
and that the measured maximum insertion loss is about 0.88 dB and the rejection in the range of 11.75 to 20 GHz is less than -30 dB.
关键词
Keywords
references
THOMSON N, HONG Jiasheng. Compact ultra-wideband micro-strip/coplanar waveguide bandpass filter [J]. IEEE Microwave and Wireless Components Letters, 2007, 17(3): 184-186.
CHEN Yucheng, LEE Chingher, HSU Chung I G. A compact CPW-fed UWB BPF using combined microstrip SIR [J]. Microwave and Optical Technology Letters, 2009, 51(4): 918-921.
YAO Binyan, ZHOU Yonggang, CAO Qunsheng, et al. Compact UWB band-pass filter with improved upper-stopband performance [J]. IEEE Microwave and Wireless Components Letters, 2009, 19(1): 27-29.
ABBOSH A M. Planar bandpass filters for ultra-wideband applications [J]. IEEE Trans on Microwave Theory and Techniques, 2007, 55(10): 2262-2269.
CHEN P, WEI F, SHI X W, et al. A compact ultra-wideband band-pass filter with defected ground structure [J]. Microwave and Optical Technology Letters, 2009, 51(4): 979-981.
YANG Yongjie, SUI Huijing, ZHOU Lihen, et al. Applications of novel spiral shaped defected ground structure to lowpass filter [J]. Journal of Nanjing University of Science and Technology: Natural Science, 2010, 34(6):796-798.
ROUHI R. Compact elliptic function lowpass filter based on defected ground structure [J]. IECE Electronics Express, 2010, 7(6): 434-439.
VERMA A K, KUMAR A. Synthesis of microstrip lowpass filter using defected ground structures [J]. IET Microw Antennas Propag, 2011, 5(12): 1431-1439.
WEI Feng, HUANG Qiulin, SHI Xiaowei, et al. Design and realization of a new UWB band-pass filter [J]. Journal of Microwave, 2010, 26(3): 48-51.
SEKAR V, ENTESARI K. Miniaturized UWB bandpass filters with notch using slow-wave CPW multiple-mode resonators [J]. IEEE Microwave and Wireless Components Letters, 2011, 21(2): 80-82.
NEDIL M, DENIDNI T A, DJAIZ A. Ultra-wideband microstrip to CB-CPW transition applied to broadband filter [J]. Electronics Letters, 2007, 43(8): 464-466.
CHU Qingxin, HUANG Jianquan, LIU Chuanyun. Compact UWB band-pass filter based on CRLH structure [J]. Journal of Tianjin University, 2011, 40(4): 359-363.
MONDAL P, MANDAL M K, CHAKTABARTY A. Compact bandpass filters with wide controllable fractional bandwidth [J]. IEEE Microwave and Wireless Components Letters, 2006, 16(10): 540-542.
WENG M H, CHANG Y C, WU H W. An inverse S-shaped slotted ground structure applied to miniature wide stopband lowpass filters [J]. IEICE Trans on Electron, 2007, E90-C(12): 2285-2288.
BONACHE J, GIL I. Complementary split rings resonators(CSRRs): towards the miniaturization of microwave device design [J]. Comput Electron, 2006, 5(2/3): 193-197.