Synthesis of Symmetrical TEM-Mode Directional Couplers

Toulios, P.; Todd, Adrian Christopher

doi:10.1109/tmtt.1965.1126049

Cited by 33 publications

(6 citation statements)

References 6 publications

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“…In addition, all of the couplers are distributed symmetrically with respect to the central coupler in terms of the optimum coupling coefficients assigned to them for maximum bandwidth. The theory was developed for multisection CTD CLCs [2, 3], and will work for multisection TRD CLCs equivalently well as long as the port connections of their adjacent coupled‐line couplers are maintained to be the same, that is, the through port and the isolation port of the previous coupled‐line coupler are connected to the input port and the coupled port of the next one, respectively. That is what was adopted to obtain the two‐section CTD CLCs and TRD CLCs in Fig.…”

Section: Designs For Multisection Trd Clcsmentioning

confidence: 99%

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Properties of multisection transdirectional coupled‐line couplers

Kang

2018

IET Microwaves, Antennas & Propagation

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This study is presented to explore the properties of multisection transdirectional coupled‐line couplers (TRD CLCs) developed for bandwidth enhancement. Unlike conventional multisection contradirectional coupled‐line couplers (CTD CLCs) comprising only CTD CLCs, the proposed multisection TRD CLCs may require the combination of transdirectional and CTD CLCs for some higher‐order designs. The designs feature a central TRD CLC. A symmetrical structure with respect to the central coupler is proposed to meet the port assignments of transdirectional couplers with broadband performance on the magnitude difference as well as the phase difference of 90° between two output ports. It can offer multiple solutions for some multisection designs. Practical examples are presented for 3 dB multisection TRD CLCs with optimum coupling coefficients assigned to individual couplers to achieve maximum bandwidth. Periodic structures are used to implement coupled‐line couplers. Simulation results indicate that the proposed multisection designs meet the required port assignments and offer wider bandwidth compared to a single design of the same coupling. The simulation results of the three‐section design are verified experimentally and good agreement is observed.

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Section: Designs For Multisection Trd Clcsmentioning

confidence: 99%

“…There have been many techniques presented to enhance the bandwidth of coupled‐line couplers. They are exclusively developed for contradirectional coupled‐line couplers (CTD CLCs) [2–4] and codirectional coupled‐line couplers [5, 6]. Bandwidth enhancement of TRD CLCs has never been explored.…”

Section: Introductionmentioning

confidence: 99%

Properties of multisection transdirectional coupled‐line couplers

Kang

2018

IET Microwaves, Antennas & Propagation

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“…Thus, we can determine the parameters of the lumped‐element components shown in Figure by applying a matrix formulation between a conventional transmission line and its equivalent circuit as follows :…”

Section: Design Of the Miniaturized Gysel Power Divider Using Lumped‐mentioning

confidence: 99%

Reduced‐size gysel power dividers using lumped‐element components

Tang

Hayashi

Ueda

2016

Micro & Optical Tech Letters

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means the corresponding number of the ZEM units on each column.The simulated results of the beamwidth and gain at 35GHz are concluded in Table 1. With the number of unit increases, the beamwidth of the E-plane decreases, while that of the Hplane changes little. Comparing to the antenna without ZEM units, the gain of the antenna with ZEM units is improved. The antenna of (1,1,3,5,7,9,9) arrangement has the maximum gain of 12.8dBi, but there's a big difference between the E-and Hplane beamwidths. In order to realize the high gain and equal Eand H-plane beamwidths, the antenna of (1,1,1,3,3,3,1) arrangement is chosen as the final antenna design. Antenna MeasurementsIn order to validate the propose antenna prototypes, the antenna of (1,1,1,3,3,3,1) arrangement is fabricated as shown in Figure 10. The antenna without ZEM units is also fabricated for comparison. The 2.4-mm end launch connector is utilized for measurement. The reflection coefficient is measured by the Agilent vector network analyzer of N5227A, and the radiation characteristics are measured in the anechoic chamber.The simulated and measured reflection coefficients of the two antennas are shown in Figure 11(a). It is found that the S 11 are lower than 210 dB over 26.5 GHz-40 GHz for both antennas. The simulated and measured gains are shown in Figure 11 (b). From simulation, the ZEM loaded antenna has a gain from 9.7dBi to 12.2dBi over 26.5 GHz to 40GHz with the maximum gain enhancement being 3.4dB. The measured gain varies between 9.5dBi and 12.1dBi, which agrees with the simulated results.The normalized simulated and measured radiation patterns of the ZEM loaded antenna at 27 GHz, 35 GHz and 40 GHz are shown in Figure 12. The measured E-and H-plane beamwidths at 35 GHz are 508 and 43.58, and the antenna exhibits approximate equal beamwidths. The front-to-back ratio is about 30 dB and the cross polarization is better than 18dB. The differences between the simulation and measurement are caused by the fabrication errors and the end-launch connector. CONCLUSIONIn this paper, the Vivaldi antenna with high front-to-back ratios, harmonic suppress and broad bandwidth at Ka band is proposed. By loading the ZEM units, the gain enhancement has been obtained in the frequency band of 26.5 GHz-40 GHz. The measured front-to-back ratio is 30 dB and the cross polarization is better than 18dB. In addition, the nearly equal beamwidths in E-and H-plane are achieved at 35 GHz. The proposed antenna has simple structure and low cost, which could be applied in wireless power transmission and millimeter wave imaging systems.ABSTRACT: This letter presents two novel prototypes of reduced-size Gysel power dividers using 908 and 61808 lumped-element components. The first design is a Gysel power divider using 908 and 1808 lumpedelement components. The ideal divider designed at a frequency of 590 MHz exhibits power splits of 23.2 6 0.2 dB and return losses of greater than 15 dB for the frequency range of 530 to 710 MHz. The second design is a Gysel power divider using 908 and 21808 ...

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“…When operating at cryogenic temperatures, the design of a device must take into consideration material properties, i.e., thermal contraction coefficients, dielectric properties, in order to match the different layers with different materials required to minimize the linear strain and conductor offset due to the induced stress caused by the cooling [5]. Multisection layouts are usually employed when multi-octave bandwidths are required [6], [7]. In practice, such couplers require the strongest coupling in the middle section, resulting in an increased sensitivity to layout dimensions such as stripline offsets, which in turn emphasizes the importance of the substrates' alignment accuracy.…”

Section: Hybrid Designmentioning

confidence: 99%

“…The structure was designed first by defining the required overall coupling factor to be 3 ± 0.2 dB over the 4-8 GHz IF bandwidth using a three-section coupler. The even mode characteristic impedance for each stage can be found in tables for a given equi-ripple across the band [6], [7]. The even mode (Z 0e ) impedances are then used together with Equations (8) and (9) to calculate the coupling coefficient for each section.…”

Section: Three Section Hybrid and Bias-t Layoutmentioning

confidence: 99%

Superconducting 4–8-GHz Hybrid Assembly for 2SB Cryogenic THz Receivers

Rashid

Meledin

Desmaris

et al. 2014

IEEE Trans. THz Sci. Technol.

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We present here the design and characterization of an intermediate frequency (IF) assembly comprising a compact 90° hybrid chip (coupled line coupler-Lange coupler-coupled line coupler), two bias-T circuits for biasing the Superconductor-Insulator-Superconductor (SIS) mixers, and two transmission line circuits. Specifically, the miniaturized 3-section hybrid chip fabricated using thin-film technology utilizes superconducting Niobium (Nb) transmission lines, air bridges to connect the fingers of the Lange coupler (middle section), and is complemented with two bias-T circuits with integrated MIM capacitors. The assembly was designed to ensure amplitude and phase imbalances better than 0.6 dB and ±2° respectively. Experimental verification of the assembly at 4 K shows good agreement between the measurements and simulations with amplitude imbalance of 0.5 dB and maximum phase imbalance of ±2°. The ALMA band 5 (163-211 GHz) receiver will include such assembly. The receiver tests shows sideband rejection ratio better than 15 dB over the entire RF band, i.e. a systematic improvement of 3-9 dB as compared to the previously reported results.

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Synthesis of Symmetrical TEM-Mode Directional Couplers

Cited by 33 publications

References 6 publications

Properties of multisection transdirectional coupled‐line couplers

Properties of multisection transdirectional coupled‐line couplers

Reduced‐size gysel power dividers using lumped‐element components

Superconducting 4–8-GHz Hybrid Assembly for 2SB Cryogenic THz Receivers

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