2Ultra-Wideband (UWB) Bandpass Filter With Embedded Band Notch Structures (1) Proposed UWB BPF with embedded band notch stubs.Predicted and the measured results for Filter-A with the FCC indoormask.
3Ultra-Wideband (UWB) Bandpass Filter With Embedded Band Notch Structures (2) Insertion loss of the embedded stub with varying gap forWs =0.1mm and Wc = 1.3 mm.Schematic diagrams of (a) conventional open-circuited stub, (b) spurline, and (c) proposed embedded open-circuited stub.Full-wave EM simulation of the complete layout of the designed UWB BPF with varying equal stub lengths.
4Ultra-Wideband (UWB) Bandpass Filter With Embedded Band Notch Structures (3) 製作於FR4板、介電常數為 3.05 基板高度0.508 損失0.025不具有傳輸零點具有一個可調式notched band結構尺寸22.2mm X 15.1mm，大約為1.07λg X 0.54λg。中心頻率在5.83GHz
6Investigation in Open Circuited Metal Lines Embedded in Defected Ground Structure and Its Applications to UWB Filters (1)Schematic diagrams of (a) top view of proposed UWB BPF, (b) bottom view of proposed UWB BPF, (c) top view of proposed UWB BPF with notch band implementation, (d) bottom view of proposed UWB BPF with notch band implementationSimulated and measured results of Fabricated UWB BPF.
7Investigation in Open Circuited Metal Lines Embedded in Defected Ground Structure and Its Applications to UWB Filters (2)製作於FR4板、介電常數為4.4、基板高度0.8、損失為0.025。具有兩個傳輸零點，分別在1.65GHz和11.36GHz。具有一個notched band 。(只可控制頻寬)結構尺寸11.7mm X 6.3mm、大約為0.41λg X 0.22λg。中心頻率為 5.5GHz
9Ultra Wideband Bandpass Filter with Dual Notch Bands (1) Simulated and measured frequency responses and (b)group delay of the fabricated UWB BPF. The dimensions are W1 = 0.1, W 2 = 0.7, W 3 = W 5 = 1.8, W 4 = 0.7, Lc = 4, L1 = 4.4, L2 = L4 = 2, L3 = 3.3, L5 = 4.2, d = 4.2, S1 = 0.1, S2 = S3 = 0.2. All are in mm.Structure of the proposed UWB filter
10Ultra Wideband Bandpass Filter with Dual Notch Bands (2) (a) Structure of the square etched MMR and (b) |S21|- magnitude of the MMR with different coupled line lengths (Lc).|S21|-magnitude
11Ultra Wideband Bandpass Filter with Dual Notch Bands (3) |S21|-magnitude in comparisonof SIR 1SIR 2 with tuning 1.
12Ultra Wideband Bandpass Filter with Dual Notch Bands (4) 製作於Duroid 6010板、介電常數為10.2、基板高度為1.27、損失0.0023。整個通帶從3.1GHz~11GHz。不具有傳輸零點。具有兩個可調式notched band 。結構尺寸為13.4mm X 8.62mm。
14Compact Ultra-Wideband Bandpass Filter Using Dual-Line Coupling Structure(1) Simulated and measured results of the fabricated BPF with spuriousresponse suppression.Topology of the compact UWB BPF
15Compact Ultra-Wideband Bandpass Filter Using Dual-Line Coupling Structure(3) 超寬帶帶通 4.9和10.9GHz返回損失超過 15db從 5.7至10.7GHz在1分貝插入損耗約 5GHz帶寬，最小插入損耗為 0.49 dB的7.3GHz。S-parameters and group delay of the UWB BPF.
17A New Dual-Band Microstrip Bandpass Filter Using Net-Type Resonators
18INTRODUCTIONλ/2 SIRs shown in Fig. 1(a-1) and (a-2) are employed to design dual-band filters with two passbands at frequencies ƒ1 and ƒ2 (ƒ2 > ƒ1) . The frequency ratio ƒ2/ƒ1 determines which type of SIRs ( K <1 or K>1 ) should be adopted.
19INTRODUCTIONλ/4 SIR shown in Fig. 1(b-1) was evolved into the net-type resonator  depicted in Fig. 1(c-1) and (d-1), and then exploited to design a single passband filter.
20INTRODUCTIONthe net-type resonator in the K>1 region shown in Fig. 2 is developed to achieve two closely specified resonant frequencies. The filter developed in this letter not only has two transmission zeros to improve the selectivity of each passband, but also providesa wide stopband suppression and an excellent mid-bandrejection between two passbands.Fig. 2. Spurious resonant frequencies of the λ/4 stepped-impedance resonatorWith K=Z2/Z1 <1 and K=Z2/Z1 >1
21DUAL-BAND NET-TYPE RESONATOR To design the λ/4 SIR with two close resonant frequencies, ƒ1 and ƒ2 (ƒ2/ƒ1 ≈ 2). It is comprised of two transmission lines with the equal electrical length and the impedance ratio K=Z2/Z1 > 1.The high impedance (Z2) line is kept open-circuitedwhile the low impedance (Z1) line is connected to theground. Hence, the first two resonant frequencies f1 and f2 (f2 > f1) of this λ/4 SIR
22DUAL-BAND NET-TYPE RESONATOR Since the electrical lengths of two sections of the SIR are set to equal,the net-type resonator can be folded to a square box shape as shown in Fig. 1(d-2).The low impedance line can be equivalent to three parallelconnected stubs as shown in Fig. 1(c-2).
23DUAL-BAND NET-TYPE RESONATOR Note that neither the value of K nor ƒ2/ƒ1 is restricted to an integer. Fig. 3 shows the resonant frequencies of the net-type resonators with K = 1.57 (ƒ2/ƒ1 = 2.5) and K = 3 (ƒ2/ƒ1 = 3)Fig. 3. Resonant frequencies of the net-type resonator with K = 1.57 and 3.
24DESIGN OF DUAL-BAND FILTER The resonators 1 and 4 are designedto simultaneously operate at the center frequencies ƒ1 and ƒ2 of he first and second passbands.The resonators 2I and 3I are designed to operate at ƒ1while the resonators 2II and 3II are designed to operate at ƒ2(a) Coupling structure
25DESIGN OF DUAL-BAND FILTER The filter is fabricated on a RO4003 substrate with a thickness of mm, a dielectric constant of 3.38, and a loss tangent ofThe center frequencies of two passbands are setTo ƒ1 =1 GHz and ƒ2 =2 GHzschematic layout of the dual-band BPFusing net-type resonators.
26DESIGN OF DUAL-BAND FILTER Substituting ƒ1 and ƒ2 into (1), one can obtain the impedance ratio K = 3 , and then calculate the electrical length Ɵ = 60o(1)using (2). Here Z1 and Z2 are chosen as 60Ω and 20Ω , respectively.(2)The fractional bandwidths (FBWs) of first and second passbands are ∆1 = 4.6% and ∆ 2 = 4.8%
27SIMULATED AND MEASURED RESULTS It occupies a circuit size of X mm2. The simulated and measured results are illustrated in Fig. 5(b), and their enlarged views of the responses are given in Fig. 5(c).Circuit photograph of the developed filter.Simulated and measured results coveringtwo passbands and theirenlarged views of responses.
28SIMULATED AND MEASURED RESULTS the mid-band rejection between two passbands is greater than 40 dB from 1.14 GHz to 1.75 GHz.It is because the open stub in the resonator 1 or 4 individually gives a transmission zero at around 1.5 GHz.then the coupling between resonators 1 and 4 makes two transmission zeros split at 1.33 and 1.55 GHz.