Design and Analysis of Compact Single and Dual Notch Ultra Wideband Bandpass Filter

Abstract

This paper presents single and dual notch ultra-wideband bandpass filters (UWB BPFs) to mitigate interference with coexisting wireless communication systems in ultra-wideband (UWB). The single and dual notch UWB BPF is developed by using signal interaction concept loaded with stub loaded resonator. The stub loaded resonator creates notches in the passband to avoid the interference with coexisting wireless communication systems. The notch frequency can be placed at the points of interest within passband by selecting a proper length of stub loaded resonator. Transmission zeros are introduced to enhance the selectivity of stopband. It presents UWB BPF with single notch at the frequency of 6.5 GHz and dual notch at the frequencies of 6.3 GHz and 8.0 GHz. The circuit size of proposed filters is 6 mm × 6 mm and 6 mm × 6 mm. The proposed filters exhibit good performance in terms of compact size, good fractional bandwidth and sharp selectivity. All the filters are simulated and fabricated on a Rogers R03010 substrate with relative permittivity of 10.2 and thickness of 1.28 mm. There is good agreement between simulated and measured results.

Design of multiple transmission zeros-enabled compact broadband BPFs based on microstrip-to-CPW transition technology

“…The proposed structure is compared with other dual-notched UWB filters in Table 2. It can be observed from the last column Abu Nasar Ghazali and Mohd Sazid of the table that the proposed structure is compact compared to other studies [8,10,11,12,14,16,18,20,21]. The proposed structure possesses TZs at both passband edges unlike most [8,[11][12][13][14][15][16][18][19][20], whereas, others [9,10,17] possess TZs at either of the passband edges.…”

“…The proposed structure is compared with other dual-notched UWB filters in Table 2. It can be observed from the last column of the table that the proposed structure is compact compared to other studies [8, 10, 11, 12, 14, 16, 18, 20, 21]. The proposed structure possesses TZs at both passband edges unlike most [8, 11–16, 18–20], whereas, others [9, 10, 17] possess TZs at either of the passband edges.…”

“…Two complementary split ring resonator (CSRR)-shaped DGS were used to develop dual notches in [8], whereas slots in microstrip on the top in the form of spurlines [9] and CSRR [10] generated dual TZs in the passband. A very popular method of notch generation is with the use of stepped impedance resonator (SIR) along the microstrip [11][12][13][14][15][16]. The SIR in its original form [11][12][13], or in the form of simplified composite right/left-handed resonator [14], E-shaped resonator [15], or electromagnetic (EM) band gap structures [13] has dual resonance properties which help in placing two notches at points of interest in the passband.…”

“…A very popular method of notch generation is with the use of stepped impedance resonator (SIR) along the microstrip [11][12][13][14][15][16]. The SIR in its original form [11][12][13], or in the form of simplified composite right/left-handed resonator [14], E-shaped resonator [15], or electromagnetic (EM) band gap structures [13] has dual resonance properties which help in placing two notches at points of interest in the passband. Folded microstrip lines utilize the principle of wave cancellation for generation of two TZs in [17].…”

“…The authors in [22,23] report work on tunable passband notches. However, most of the structures mentioned above possess several drawbacks in the form of absence of TZs [8,[11][12][13][14][15][16][17][18][19][20] which leads to poor selectivity [11,[13][14][15][16]18], poor return/insertion loss [9,[11][12][13][14][16][17][18], large size [8, 10-12, 14, 16, 18, 20, 21], and complex geometry due to presence of vias [11-16, 18, 20] or limitation in fabrication caused by minimum dimension [10,17].…”