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A diplexer realized purely based on direct coupling is presented. No cross-coupling is involved in the design process. The microwave diplexer is achieved by coupling a dual-band bandpass filter onto two individual channel filters. This design eliminates the need for employing external junctions in diplexer design, as opposed to the conventional des...
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... 10-pole dual-band filter (DBF) was also designed using the method presented in [21]. The DBF was designed to operate at the center frequency of the proposed diplexer, with a combined FBW of 8% (with equal split of 4% each, for the upper and the lower passbands). The upper and lower passbands of the DBF, respectively, agrees with BPF1 and BPF2 in terms of number of poles, FBW and center frequency. The DBF is also designed to have a 20 dB return loss and 50 Ohms termination. Table 2 shows the numerical design parameters for the DBF. The diplexer circuit model was established by cou- pling the first pair of dual-band resonators of the DBF, onto the last four resonators of the transmit channel filter (BPF1) and the last four resonators of the receive channel filter (BPF2). In other words, the first resonator of each of the 5th order BPF of Tab. 1 is replaced with a dual-band resonator from the DBF of Tab. 2 as shown in Fig. 2 (c). D1 and D1' are the first pair of dual-band resonators from the DBF; T2, T3, T4, T5 and R2, R3, R4, R5 are the last four resonators of BPF1 and BPF2 respectively. as shown in Fig. 3. The coupling between resonators in the proposed diplexer circuit model is mainly asymmetrical coupling since the diplexer is made up of three different filters, namely the DBF, BPF1 and BPF2, which all have different center frequencies as shown in Tab. 1 and ...
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Citations
... A microstrip diplexer has been created by combining two separate channel filters to a dual-band bandpass filter [13]. This design avoids the requirement for external junctions in the construction of diplexers, in contrast to the conventional design method that necessitates separate connections or junctions for energy distribution. ...
This paper presents a low-insertion-loss open-loop resonator (OLR)-based microstrip diplexer with high-selective for wireless applications. We used two series capacitive gaps in the microstrip transmission line, loaded with rectangular-shaped half-wavelength OLRs, to create a high-selectivity bandpass filter (BPF). The planned BPFs are linked through a T-junction combiner, precisely tuned to align with both filters and the antenna port in order to produce the proposed diplexer. The system is implemented on a rogers TMM4 substrate with a loss tangent of 0.002, a dielectric constant of 4.7, and a thickness of 1.52 mm. The suggested diplexer has dimensions of (90×70) mm². It achieves a modest frequency space ratio of R=0.1646 in both transmit and receive modes by having two resonance frequencies of ft=2.191 GHz and fr=2.584 GHz, respectively. The simulated structure displays good insertion losses of approximately 1.2 dB and 1.79 dB for the two channels, respectively, at fractional bandwidths of 1.24% at 2.191 GHz and 0.636% at 2.584 GHz. The simulated isolation values for 2.191 GHz and 2.584 GHz are 53.3 dB and 66.5 dB, respectively.
... Several types of microstrip diplexers are presented in references [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], but the main drawback is that they require a lot of space. Reference [7] proposes a Y-shaped slot antenna with a cavitybacked self-diplexing system using substrate integrated waveguide (SIW) to achieve high isolation. ...
... In reference [13], a dual-band bandpass filter was created by merging two independent channel filters to establish a microstrip diplexer. This approach eliminates the requirement for external junctions during the diplexer's construction, which diverges from conventional techniques that demand separate connections or junctions for distributing energy. ...
... , 12 = 9.8. ,13 = 3.2. , 14 = 0.15. ...
This paper presents a high-selectivity, low-insertion-loss open-loop resonator (OLR)-based microstrip diplexer designed for wireless communication systems. We employed a microstrip transmission line with two serial capacitive gaps, incorporating rectangular half-wavelength open-loop resonators, to create a bandpass filter (BPF) with remarkable selectivity. The intended BPFs are interconnected by a T-junction combiner, which is matched to both filters and the antenna port, thereby creating the modelled diplexer. The system is implemented on a Rogers TMM4 substrate featuring a loss tangent of 0.002, a dielectric constant of 4.7, and a thickness of 1.52 mm. The suggested diplexer has dimensions of (90×70) mm². It achieves a modest frequency spacing ratio of R=0.1646 in both transmit and receive modes, with resonance frequencies of ft = 2.191 GHz and fr = 2.584 GHz, respectively. The simulated structure demonstrates favorable insertion losses of approximately 1.2 dB and 1.79 dB for the two channels at fractional bandwidths of 1.24% (2.191 GHz) and 0.636% (2.584 GHz). The simulated isolation values at 2.191 GHz and 2.584 GHz are 53.3 dB and 66.5 dB, respectively. Notably, the simulated and measured results exhibit a high degree of consistency. However, minor variations between the simulated and actual results have been noted, primarily attributable to the inherent fabrication tolerances.
... Two independent channels that operate at two different desired frequencies are created by the diplexer devices by splitting the input signal from a single input port [18,19]. Various varieties of microstrip diplexer are introduced in [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. They all, however, take up a lot of room. ...
... However, it did had sizable insertion losses of 2.88 dB and 2.95 dB in the transmit and receive bands, respectively. In [27], a novel microstrip diplexer with excellent isolation and selectivity was introduced. ...
... Many different resonator types are employed [28][29][30][31][32][33][34][35][36][37][38] to enhance frequency response performance. Other resonator forms, such U-shaped [28] and T-shaped [27], have recently been developed. Pi-shaped [21], stepped-impedance [22], and Patch [23,24] resonators. ...
This paper presents a Highly Isolation open-loop resonators (OLR)—based microstrip full-duplex Tx/Rx antenna systems with low insertion loss for contemporary wireless system applications. Through a T-junction combiner, the proposed diplexer is accomplished by combining two OLR—based band-pass filters tuned at two distinct frequencies. The system is implemented on a Rogers TMM4 substrate with a loss tangent of 0.002, a dielectric constant of 4.7, and a thickness of 1.52 mm. The suggested full duplex has dimensions of (90 × 70) mm². It achieves a modest frequency space ratio of R = 0.1646 in both transmit and receive modes by having two resonance frequencies of ft\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${f}_{t}$$\end{document} = 2.191 GHz and fr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${f}_{r}$$\end{document} = 2.584 GHz, respectively. The simulated structure displays good insertion losses (IL) of approximately 1.2 dB and 1.79 dB for the two channels, respectively, at fractional bandwidths of 1.24% at 2.191 GHz and 0.636% at 2.584 GHz. The simulated isolation values for 2.191 GHz and 2.584 GHz are 53.3 dB and 66.5 dB, respectively.
... This is due to its small size of approximately 1/8 of a quarter-wavelength along each side of the square [1]. The popularity and versatility of the SOLR in filter design means that numerous researchers have used it in implementing their designed filtering components [2][3][4][5][6][7][8][9][10][11][12]. ...
... This is due to its small size of approximately 1/8 of a quarterwavelength along each side of the square [1]. The popularity and versatility of the SOLR in filter design means that numerous researchers have used it in implementing their designed filtering components [2][3][4][5][6][7][8][9][10][11][12]. The modern-day electromagnetic (EM) spectrum is becoming overcrowded and is heavily crammed with a variety of wireless signals and other communication and sensing circuits and components. ...
... Take space crafts for example, and it may be seen that compact filters are employed in the design of diplexers used in the satellite communication systems of space crafts. This is because space crafts are built to an effective reduced mass and volume, as highlighted in [3]. Other receiver applications of the proposed filter include radar, drones, Wi-Fi, etc. ...
Folded-arms square open-loop resonator (FASOLR) is a variant of the conventional microstrip square open-loop resonator (SOLR) that facilitates further device size miniaturization by having the two arms of the conventional SOLR folded inwards. This paper highlights the benefits of this brand of compact SOLR by implementing a five-pole Chebyshev bandpass filter (BPF) using compact FASOLR. The test BPF is presented, with centre frequency of 2.2 GHz, fractional bandwidth of 10%, passband ripple of 0.04321 dB, and return loss of 20 dB. The design is implemented on a Rogers RT/Duroid 6010LM substrate with a dielectric constant of 10.7 and thickness of 1.27 mm. The filter device is manufactured and characterised, with the experimentation results being used to justify the simulation results. The presented measurement and electromagnetic (EM) simulation results demonstrate a good match. The EM simulation responses achieve a minimum insertion loss of 0.8 dB and a very good channel return loss of 22.6 dB. The measurement results, on the other hand, show a minimum insertion loss of 0.9 dB and a return loss of better than 19.2 dB. The filter component has a footprint of 36.08 mm by 6.74 mm (that is, 0.26 λg x 0.05 λg), with λg indicating the guided wavelength for the 50 Ohm microstrip line impedance at the centre frequency of the proposed fifth-order bandpass filter.
... This presents the potential to develop microwave diplexers with enhanced performance. In [15], crosscoupled open-loop resonators are developed for microstrip diplexer applications with improved channel isolations. This paper reports our recent research on a dual-mode loop resonator with in-line feed-lines for application to the microwave diplexers. ...
In this paper, a dual-mode loop resonator based circuit topology is studied for microwave diplexer applications. Several diplexers, with dense and sparse channel separations, are further discussed based on the introduced topology, featuring capable of controlling transmission zeros flexibly. Hence microwave diplexers with high selectivity and good channel isolation can be realized by placing transmission zeros of the channel filters at the desired channels. With the use of the proposed topology, the achieved center frequency ratio between two channels can be from 1.03 to 1.35 with good isolations, high selectivity and compact size. The demonstration diplexers are realized on PCB processes, but can be implemented with other media including MMIC. Experimental validations on the developed demonstrator are presented in the paper, and measured responses match well the full-wave electromagnetic simulated results. The developed UMTS diplexer demonstrator achieves the measured minimum passband insertion losses of 2.55 and 2.7 dB with return losses better than 15 dB and channel isolations over 40 dB at the two channels.
... This is due to its small size of approximately 1/8 of a quarter-wavelength along each side of the square [1]. The popularity and versatility of the SOLR in filter design means that numerous researchers have used it in implementing their designed filtering components [2][3][4][5][6][7][8][9][10][11][12]. ...
Folded-arms square open-loop resonator (FASOLR) is a variant of the conventional microstrip square open-loop resonator (SOLR) that facilitate further device size miniaturization by having the two arms of the conventional SOLR folded inwards. This paper highlights the benefits of this brand of compact SOLR by implementing a five-pole Chebyshev bandpass filter (BPF) using the compact FASOLR. The test BPF, with centre frequency of 2.2 GHz, fractional bandwidth of 10%, passband ripple of 0.04321 dB, and return loss of 20 dB is presented. The design is implemented on Rogers RT/Duroid 6010LM substrate with a dielectric constant of 10.7 and thickness of 1.27 mm. The filter device is manufactured and characterised, with the experimentation results used to justify the simulation results. The presented measurement and electromagnetic (EM) simulation results demonstrate good match. The EM simulation responses achieved a minimum insertion loss of 0.8 dB and a very good channel return loss of 22.6 dB. The measurement results, on the other hand, show a minimum insertion loss of 0.9 dB and a return loss of better than 19.2 dB. The filter component has a footprint of 36.08 mm by 6.74 mm (that is, 0.26λg x 0.05λg), with λg indicating the guided wavelength for the 50 Ohm microstrip line impedance at the centre frequency of the proposed fifth order bandpass filter.
... Despite its tiny size, this diplexer offered high selectivity, low insertion loss, and good isolation larger than 40 dB, according to the presented simulation and measurement results. In [5], a new microstrip diplexer has been developed by coupling a dual-band bandpass filter via two individual channel filters. In contrast to the traditional design technique, which requires separate connections or junctions for energy distribution, this design eliminates the need for external junctions in diplexer construction. ...
In this paper, the design and hardware implementation of a squared open-loop resonator (SOLR)-based microstrip diplexer with high isolation, low insertion loss, and high selectivity are introduced. We employed four SOLRs, with each pair of coupled SOLRs used to build a high selectivity bandpass filter (BPF). To assemble the proposed diplexer, the designed BPFs are linked together via a T-junction combiner that is matched to the two filters and the antenna port. For transmit and receive modes, the proposed diplexer has two resonance frequencies of ft = 1.81 GHz and fr = 2.03 GHz, respectively achieving a small frequency space ratio of R = 0.114. The simulated structure exhibits good insertion losses of about 1.98 dB and 1.9 dB for the two channels, respectively, with fractional bandwidths of 2.25% at 1.81 GHz and 3% at 2.03 GHz. For 1.81 GHz and 2.03 GHz, the simulated isolation values are 58 dB and 46 dB, respectively. While the fabricated structure exhibits better insertion losses of about 1.25 dB and 1.22 dB at the measured transmit and receive frequencies of 1.801 GHz and 2.001 GHz, respectively, with smaller fractional bandwidths of 2.23% at 1.801 GHz and 2.98% at 2.001 GHz. For 1.801 GHz and 2.001 GHz, the measured isolation values are 48.99 dB and 57.02 dB, respectively.
... The diplexer can be defined as a device to be used either for combing dual sub-band into single common wide band, or dividing the frequency band into dual separated sub-bands. Generally speaking, the microwave diplexers are employed to connect two networks with diverse in service frequencies to the common port [2]. ...
In this paper, the miniaturized microstrip diplexer has been designed for dual channels based on FR4 substrate material. It consists of two bandpass filters (BPFs) functioning under dissimilar frequency bands coupled with a unified junction. Every BPF has been created by a meandered line resonator, step impedance resonator, uniform impedance resonator, and input/output feed lines. The AWR electromagnetic simulator has been used for characterizing the frequency responses of the projected diplexer. Noble scattering parameter results with narrow band responses and negative group delay values are obtained for the proposed diplexer. The microstrip diplexer has an interesting band isolation between the two filters around 31 dB. The device has been successfully fabricated and verified with the simulations.
... The microstrip square open-loop resonator (SOLR) [17][18][19] and hairpin resonator (HPR) [20] were used in the layout implementation of the proposed FPS. The SOLR and each HPR were designed to resonate at f0. ...
A compact unbalanced two-way filtering power splitter with an integrated Chebyshev filtering function is presented. The design is purely based on formulations, thereby eliminating the constant need for developing complex optimization algorithms and tuning, to deliver the desired amount of power at each of the two output ports. To achieve miniaturization, a common square open-loop resonator (SOLR) is used to distribute energy between the two integrated channel filters. In addition to distributing energy, the common resonator also contributes one pole to each integrated channel filter, hence, reducing the number of individual resonating elements used in achieving the integrated filtering power splitter (FPS). To demonstrate the proposed design technique, a prototype FPS centered at 2.6 GHz with a 3 dB fractional bandwidth of 3% is designed and simulated. The circuit model and layout results show good performances of high selectivity, less than 1.7 dB insertion loss, and better than 16 dB in-band return loss. The common microstrip SOLR and the microstrip hairpin resonators used in implementing the proposed integrated FPS ensures that an overall compact size of 0.34 λg × 0.11 λg was achieved, where λg is the guided-wavelength of the 50 Ω microstrip line at the fundamental resonant frequency of the FPS passband.
... Furthermore, several filter structures based on microstrip and SIW are employed to design planar diplexers [15][16][17][18][19][20][21][22][23][24][25][26][27]. A compact diplexer is developed by utilizing the multiple resonant modes in the SIW cavity [15]. ...
... In [19], dual-mode SIW resonators are combined together to design a compact diplexer. In [20], a planar microstrip diplexer is realized based on direct coupling. A SIW diplexer is designed employing input/output coupling in [21]. ...
... In [27], a SIW diplexer is realized based on mode suppression technique. It is observed that the isolation is larger in [17][18][19][20][21], [23][24][25] and smaller in [15,16,22,26,27]. Also, it is noted that these diplexers occupy larger circuit area with large insertion loss. ...
This paper presents a novel design of minia-turized substrate-integrated waveguide (SIW) filter loaded with a pair of unit-cell resonators. Two identical open-loop resonators are connected face-to-face to form a unit-cell. A pair of unit-cells is engraved on the surface of the SIW to develop an evanescent-mode bandpass filter. The proposed unit-cells behave as an electric-dipole and produce a passband smaller than the waveguide frequency. This reduction in resonant frequency allows us to achieve size miniaturization. An equivalent electrical-circuit model is developed and investigate for characterization of passband and transmission-zero. This filter structure is then employed to develop a SIW planar diplexer. Two SIW filter structures loaded with unit-cells are excited with a T-shaped feed line to achieve lower and upper channels of the diplexer. To demonstrate the analysis, both SIW filter and diplexer loaded with open-loop resonators are implemented and fabricated. The proposed SIW filter and diplexer prototypes exhibit size miniaturization, low insertion-loss and high-selectivity due to evanescent-mode transmission and sub-wavelength res-onators. The measurement responses are very similar to the simulation responses.
