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A novel design method of microstrip diplexer without extra matching circuit is proposed in this paper. Because of the synthesizable circuit parameters and controllable transmission zeros (TZs) in composite resonator (CR) cell, diplexer A based on CR cell is proposed. By allocating TZs at center frequency of the opposite channel, as well as the usin...
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Citations
... λ is the wavelength corresponding to the central frequency of the passband. In this way, each BPF input is equivalent to a short circuit for another BPF and becomes an open circuit after λ /4 impedance transformation, so the two BPFs do not affect each other [34]. It is worth noting that small changes to the size of a di-plexer can have a significant effect on its tuning due to unwanted coupling between the tight resonators. ...
This letter presents a new microstrip diplexer with self-packaged and wide bandwidth based on substrate-integrated suspended line (SISL) technology. Diplexer consists of D-CRLH filters which include mixed coupling. The electromagnetic interaction is canceled out in the filter, generating two transmission zeros and giving the filter good stopband suppression. Diplexer utilizes a T-junction to make filters work in parallel. Each channel filter can be individually controlled. To validate the proposal, a diplexer operating at 1.88 GHz and 2.64GHz with fractional bandwidth (FBW) of 14.6% and 19.1% is designed and fabricated. A good agreement is perceived between measured and simulated.
... Compactly designed diplexers are expounded upon in [5][6][7], while Refs. [8,9] introduce methods for crafting highly selective and isolation-optimized diplexers. On a different note, a novel approach to diplexer and triplexer design is posited in [10], eliminating the need for ancillary matching circuits by employing an open/shorted SLR. ...
... Equation (9) gives us transfer matrix [T] BPF2 as can be seen in Figure 3: Similarly, the procedure for the synthesis of a second bandpass filter involves evaluating the complex filtering function. Furthermore, since the two bandpass filters are parallel to each other, the overall response is obtained by multiplying the transfer functions obtained from Equations (1) and (9). This research proposes a diplexer structure consisting of two bandpass filters. ...
This paper presents the design of microstrip-based multiplexers using stub-loaded coupled-line resonators. The proposed multiplexers consist of a diplexer and a triplexer, meticulously engineered to operate at specific frequency bands relevant to IoT systems: 2.55 GHz, 3.94 GHz, and 5.75 GHz. To enhance isolation and selectivity between the two passband regions, the diplexer incorporates five transmission poles (TPs) within its design. Similarly, the triplexes filter employs seven transmission poles to attain the desired performance across all three passbands. A comprehensive comparison was conducted against previously reported designs, considering crucial parameters such as size, insertion loss, return loss, and isolation between the two frequency bands. The fabrication of the diplexer and triplexer was carried out on a compact Rogers Duroid 5880 substrate. The experimental results demonstrate an exceptional performance, with the diplexer exhibiting a low insertion loss of 0.3 dB at 2.55 GHz and 0.4 dB at 3.94 GHz. The triplexer exhibits an insertion loss of 0.3 dB at 2.55 GHz, 0.37 dB at 3.94 GHz, and 0.2 dB at 5.75 GHz. The measured performance of the fabricated diplexer and triplexer aligns well with the simulated results, validating their effectiveness in meeting the desired specifications.
... The resonant frequency of the switchable resonator can be changed by manipulating the diode's bias state. Paper [14] has developed a diplexer that eliminates the need for an external matching circuit is proposed. Allocating TZs at the center frequency of the opposite channel and making use of the impedance transformations provided by the J-inverters allows for high isolation and good passband selectivity. ...
... It is common practice to use a T-junction for connecting several BPFs that have been tuned to the same frequency so that they can continue to match and remain isolated from one another. Tjunctions can be viewed as extra matching circuits in diplexers since they do not contribute to the resonant mode and the microstrip lines connected to T-junctions always occupy extra circuit area [14]. With the use of an I/O stub-loaded resonator. ...
Communication plays an important role in life these days. Communications interfere in many applications, for example, military, medical and community systems. Communications have brought the world closer. This article shows a state of art of previous studies about many devices used in communication systems. These devices are categorized under the term microstrip devices.Filters, Diplexers, and Triplexers will be the scop
... Over the years, numerous diplexers have been developed using various topologies, including Stepped Impedance Resonators (SIR), coupled lines, Open/Shorted Stub Loaded Resonators (SLR), Squared Open Loop Resonators (SOLR), Substrate Integrated Waveguide (SIW), Stub-Loaded Square Ring Resonator (SLSRR), Composite Right/Left-Handed (CRLH) resonator, and Defected Ground Structure (DGS). This paper focuses on the design of compact diplexers, as proposed in [5]- [7], and introduces highly selective and high-isolation diplexers in [8] and [9]. Designing a matching circuit for multiplexers with more than two channels is challenging. ...
This paper presents the design of a microstrip-based diplexer for the applications of the Internet of Things (IoT). By incorporating stub-loaded coupled line resonators, the diplexer achieves significant enhancements in its passband performance. Specifically engineered to operate at precise frequencies of 2.55 GHz and 3.94 GHz, the diplexer demonstrates improved isolation and selectivity through the integration of five transmission poles (TPs). A comprehensive analysis is conducted, evaluating crucial parameters such as size, insertion loss, return loss, and isolation. The diplexer is fabricated on a compact Rogers Duroid 5880 substrate, and experimental measurements validate its effectiveness, exhibiting a low insertion loss of 0.3 dB at 2.55 GHz and 0.4 dB at 3.94 GHz, in close agreement with simulated predictions. The proposed design, featuring stub-loaded coupled line resonators, showcases highly promising passband characteristics, making it a compelling solution for efficient multiplexing of diverse frequency bands in wireless communication applications within the IoT and Network-on-chip (NoC) domains.
... However, it is found that none of the aforementioned diplexer approaches features two closely-spaced channels with multiple close-to-passband TZs at both sides of the band edges. Although single-ended and balanced microstrip diplexers with pairs of close-to-passband TZs were proposed in [11] and [12], respectively, their usefulness is limited to narrow/moderate-bandwidth channels. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. ...
A type of multilayer microstrip diplexer with highly- selective wideband filtering channels is reported. Its closely-spaced fourth-order passbands are attributed to two circuit parts: (i) two third-order quasi-elliptic-type microstrip-to-microstrip wideband vertical transitions and (ii) a shunt two-stub dual-band bandpass filter (BPF) junction printed on the top layer. The two microstrip vertical transitions are developed by means of open-/short-circuit-ended microstrip lines and slotline stepped-impedance resonators (SIRs), respectively, and they correspond to the constituent lower and upper channels. The shunt dual-band BPF junction produces one additional transmission pole and one more pair of close-to-passband transmission zeros (TZs) for each channel to further increase their filtering selectivity. The RF theoretical foundations and design procedure of the engineered broadband diplexer are detailed. For practical-validation purposes, a proof-of-concept prototype of two-layer fourth-order microstrip wideband diplexer is simulated, manufactured, and tested. Its measured lower and upper channels has two closely-spaced sharp-rejection passbands with center frequencies of 1.496 GHz and 2.759 GHz and 3-dB fractional bandwidths of 62.83% and 24.83%, respectively, while featuring power-isolation levels above 27.39 dB from 0.5 to 4 GHz.
... Each channel is used for receiving or sending signals from an antenna (Majdi and Mezaal, 2022). Several types of microstrip diplexer are introduced in (Hussein, Mezaal and Alameri, 2021;Chen, et al., 2021;Yahya, Rezaei and Nouri, 2020;Lu, et al., 2020;Su, et al., 2020;Tahmasbi, Razaghian and Roshani, 2021;Shirkhar and Roshani, 2021;Zhanga, Zhu and Li, 2018;Rezaei, Yahya, Noori and Jamaluddin, 2019;Dembele, et al., 2019;Yousif and Ezzulddin, 2020;Fernandez-Prieto, et al., 2018;Guan, et al., 2019;Guan, et al., 2014;Noori and Rezaei, 2017). However, all of them occupy large area. ...
... In (Yousif and Ezzulddin, 2020), the microstrip meandrous closed loops have been utilized to design of a diplexer with good measured return losses. The problem of high losses has been remained in the presented diplexers in (Fernandez-Prieto, et al., 2018;Guan, et al., 2019;Guan, et al., 2014;Noori and Rezaei, 2017). ...
This paper presents an efficient theoretical design approach of a very compact microstrip diplexer for modern wireless communication system applications. The proposed basic resonator is made of coupled lines, simple transmission line and a shunt stub. The coupled lines and transmission line make a U-shape resonator while the shunt stub is loaded inside the U-shape cell to save the size significantly, where the overall size of the presented diplexer is only 0.008 λg 2. The configuration of this resonator is analyzed to increase intuitive understanding of the structure and easier optimization. The first and second resonance frequencies are f o1 = 895 MHz and f o2 = 2.2 GHz. Both channels have good properties so that the best simulated insertion loss at the first channel (0.075 dB) and the best simulated common port return losses at both channels (40.3 dB and 31.77 dB) are achieved. The presented diplexer can suppress the harmonics acceptably up to 3 GHz (3.3 f o1). Another feature is having 31% fractional bandwidth at the first channel.
... Theses diplexers are of such importance that have compact size, good selectivity, high isolation and broad stop band performance. To cover all or some of these characteristics, many diplexer configurations are investigated and developed using different technologies [7][8][9][10][11][12][13][14][15][16]. ...
... Due to its power points of planar construction and circuit integration, microstrip line technology is adopted in [7][8][9][10][11][12]. Using a separate two half-complementary resonant cells, a compact diplexer is developed with good selectivity [7]. ...
... The resulted diplexer is simple in design, but the predicted passband behavior is very poor. For high isolation performance, a designable diplexer is very well analyzed and evaluated with very large circuit area [11]. In the same fashion, [12] developed a multistate diplexer for frequency hopping application. ...
This article proposes a design technique of high performance diplexer for multi-wireless networks based on multilayered u-shape resonators. In this technique, the desired passband of each filter is analysed and constructed using two substrates. On the bottom substrate, two u-shape resonators are designed and electrically coupled to specify and control the desired passband. To obtain the filtering response of the designed filter, a grounded input/output u-shape transmission line is patterned on a top substrate and vertically integrated with the bottom substrate. Indeed, two filters are realized and cascaded to perform the desired diplexer. As a result, a compact diplexer with fully independent elliptical behaviour passbands can be achieved. To verify the proposed technique, a (2.4 GHz WLAN/ 3.5 GHz WiMax) diplexer with a compact size of 23.8 mm x 11.5 mm is designed, simulated, and tested. The measurement responses are very well following the simulation results.
... In addition, based on bandstop-mode half-wavelength microstrip lines, a resonatorbased wideband diplexer with improved cut-off slopes was suggested in [5]. On the other hand, although microstrip diplexers with controllable transmission zeros (TZs) were discussed in [6], only narrow bandwidths for their two bandpass channels are attained. Consequently, one or several of the following drawbacks can still be found for all the aforementioned devices of planar diplexers: a) narrow or moderate bandwidth for the lower and/or upper channel, b) poor filtering selectivity, and/or c) degraded inter-channel powerisolation levels. ...
... An intuitive approach to synthesis a diplexer is to create a distribution network to combine two separated channels after designing each channel filter individually. Examples for diplexer channel designs include Common Mode Resonator [14], Common Stub Resonator [15], Dual Mode Resonator [16,17], Multi Coupled Resonator [18][19][20], hybrid coupler [21,22] and proper matching circuit [23,24]. The key point underlying this method is to design well-behaved BPFs connected to an optimized junction, which ensures a proper impedance matching at either frequency. ...
This paper presents a new diplexer design of a new-coupled composite right/left-handed (CRLH) resonator to serve the LTE applications. The realization of the diplexer is designed as coupled two zeroth order π-CRLH resonators to represent with zero electrical length and hence attaining a significant size reduction. The filters are designed to achieve a desired frequency bandwidth of 4% ∼16.7 Q-factor and ∼0.066 coupling coefficient at a centre frequency of 2.1 and 2.6 GHz with transmission zeros. The diplexer exhibits a rejection level of 15–20 dB while maintaining insertion loss of 1 dB for the Tx and Rx bands. The circuit design concepts are verified using equivalent circuit simulations, full electromagnetic simulations and experimental measurements. In conclusion, a good agreement is perceived between the measured and simulated data with size compactness of 30 × 60 mm².
... Diplexers [1]- [15] and triplexers or multiplexers [3], [5], [16]- [30] are used for splitting multifrequency band signals to different channels. In [1]- [14], the diplexers are bandpass responses for their transmission channels. To separate intermediate frequency and local oscillator signals, [15] proposed lowpass-bandpass diplexer. ...
... To separate intermediate frequency and local oscillator signals, [15] proposed lowpass-bandpass diplexer. Moreover, [1] and [4]- [11] have proposed compact diplexers; [2]- [7], [12], and [14] have proposed them for high selectivity and effective isolation. However, a matching circuit may be a difficult design when the channel number of a multiplexer is >2. ...
... For instance, in [6] two-band Q Ls are determined simultaneously when one tap point of the common resonator is selected. [14] successfully proposed diplexers without extra matching circuits and two band responses could be independently designed. However, there were no shared circuits for two band filters which might affect the circuit integrations. ...
Diplexers and triplexers are widely used in communication systems for separating frequency bands in different channels. Design issues related to preventing additional matching circuits, integrating two or three band input resonators into one-band resonator size, systematically designing each band external quality factor (QL), and avoiding loading effects are often encountered. To overcome these bottlenecks, stub-loaded resonators that feature in various negligible band loading effects are used to design proposed diplexers and triplexers. In particular, the stub-loaded resonator (SLR), used in the proposed triplexers and costing only one-band resonator size, achieves a negligible loading effect systematic procedure for designing the three bands required as external quality factors and resonant frequencies. Each SLR of the triplexers uses an integrated matching circuit in the resonator instead of an additional matching circuit outside the resonator. To our knowledge, a tapped-line feed resonator that can independently design three band external quality factors (QLs) and meet matching requirements by using one-band resonator size has not been reported thus far. All the currently proposed circuits have been verified and fabricated on RO4003C substrates.
