BALANCED POWER DIVIDERS/COMBINERS

This paper presents a new balanced-to-unbalanced (BTU) hybrid ring with arbitrary power division ratio. Standard S-parameters and mixed-mode S-parameters are adopted to describe the performance requirements of the BTU hybrid ring. A simple configuration composed of transmission lines is developed to achieve desired functions of the BTU hybrid ring with arbitrary power division ratio. The design equations are given to guide the design. A prototype with the power division ratio of 3:1 is designed to verify the theoretical prediction. The fabricated BTU hybrid ring is matched well for both balanced and unbalanced ports. The BTU power division with arbitrary power division ratio and high mode conversion suppression are also achieved.

PAGE 741 A low-loss hollow-core photonic crystal fibre (HV-PCF) which operates in the terahertz (THz) frequency range is proposed by researchers from Bangladesh. The HV-PCF has a total diameter of 2.75 mm and consists of a regular hexagonal lattice structure with four air-hole rings and a larger central air-hole. The fibre has an extremely low effective material loss of 0.0122 cm−1 obtained at 2.125 THz with 94% of air-core power fraction. PAGE 704 French and Canadian researchers present an air-filled substrate integrated waveguide (AFSIW) slot array antenna, for use in high-performance substrate integrated millimetre-wave systems. When compared with the conventional dielectric-filled SIW, the AFSIW design displays a narrower beam (44% and 18% narrower H- and E-plane half-power beamwidth), and enhanced efficiency (improved by 1.6%). Cross-section of hexagonal lattice structure of crystal fibre able to operate in THz range. PAGE 726 A balanced ring hybrid with arbitrary power division ratio was fabricated by embedding four half-wavelength microstrip lines in the single-ended ring hybrid. The design from China, displays arbitrary differential-mode power division, good common-mode suppression and low insertion loss and high realisable maximum k2. Air-filled substrate integrated waveguide slot array antenna. PAGE 717 An image-compressive sensing preprocessing algorithm is proposed by researchers from China. The collaboration reduced rank (CRR) algorithm is based on nonlocal sparsity and a nonlocal low-rank regularisation reconstruction algorithm (NLR-CS). The method outperforms current compressive sensing reconstruction methods in peak-signal-to-noise and visual perception. Photograph of balanced ring hybrid with arbitrary power division. PAGE 702 Researchers from Korea present a method for supressing surface waves on a microstrip antenna array at the millimetre-wave frequency. Complimentary split ring resonator (CSRR) structures are etched on the ground plane of a 10×2 microstrip array. Measured results show a gain improvement of 2.5 dB and a side lobe level reduction of 3.5 dB. Its light weight, low volume and thin profile make it suitable for radar applications. Image compressive sensing preprocessing algorithm proposed. Microstrip array antenna with etched on CSRR structures for supressing side waves.

In this article, a compact single‐layer filtering power divider based on third‐mode circular substrate integrated waveguide (SIW) cavities is proposed. The third‐mode SIW technique is introduced to divide an SIW cavity into three cavities and get 66% size reduction. The proposed power divider is composed of three third‐mode circular SIW cavities within a circuit with the size of a circular SIW cavity. The power is coupled from the input cavity to two output cavities through the electric coupling, separately. To achieve a more size reduction, the designed cavities are corrugated along the cutting planes. By increasing the length of the corrugated edges, the center frequency can be easily shifted to lower frequencies. In order to prove the proposed design procedure, the presented power divider with a second‐order bandpass filtering response is designed and fabricated. Reasonable agreements between the measured and simulated results are found. The measured results show that the power divider achieves an insertion loss of 1.2 dB at 5.61 GHz, return loss of higher than 14 dB, and 3‐dB fractional bandwidth of 7.8%. The results show that this power divider has the advantages of the compact size, high selectivity, and single‐layer structure.

A planar miniaturized asymmetrical four-port circuit structure based on the composite left- and right-handed transmission lines (CLRHTLs) is proposed in this paper to design a balanced-to-single-ended (BTSE) power divider (PD) with arbitrary power division. The two outputs of the power divider are in-phase, hence, the proposed circuit can be seen as the cascade of a balun and a Gysel power divider with arbitrary power division. The matrix conversion between the single-ended scattering parameters and the mixed-mode scattering parameters along with the circuit analytical formulation are presented. Finally, a prototype of the PD with 2 dB magnitude difference between its output ports is designed and fabricated. The measured results validate the proposed design approach.

Short-slot couplers are a particular type of waveguide directional coupler commonly used due to their compact size in comparison with other waveguide configurations. The common short-slot Riblet coupler is used as a 3 dB hybrid (equal power division to the coupled and the through ports) in microwave networks supporting high power and providing good performance over a moderate bandwidth. In this article, the general case of short-slot couplers with arbitrary power division is presented, in E- or H-plane configuration. Moreover, it is shown that the port closer to the input can handle either more or less power than the further port, depending on the design parameters and the length of the main guide of the coupler. Several designs in E- and H-plane are shown to introduce the concept. In addition, two experimental prototypes, with either rectangular waveguide interfaces or coaxial input/output, are manufactured and tested showing good agreement with the expected results.

Objectives: In this study, two new power splitters integrated with a novel half mode substrate integrated waveguide (HMSIW) and composite right/left-handed transmission lines (CRLH-TL) cells are presented, realized and compared to a conventional Substrate Integrated Waveguide (SIW) one. Methods: The SIW technology is characterized by a high Q factor and a low return loss, but it suffers from the massive size particularly in low frequencies bands, so to achieve practically 50% miniaturization in size with keeping the high performances of the SIW technique, HMSIW origins from SIW has been utilized. otherwise, so as to reduce the HMSIW device, size, Composite Right/Left-Handed Transmission Lines (CRLH-TL) cells are applied. The designs are printed on a Roger RT/duroid 6010 and performed within an HFSS environment based on the finite element method (FEM). Simulations and measurements of the three power dividers are presented over a frequency band from 2.2 GHz to 2.6 GHz. Findings: The novel proposed component achieves about 70% and 90% of size reduction compared to, respectively, the HMSIW and SIW power splitters. The simulated and measured results are in close agreement. Application: Compared to the SIW power divider and the HMSIW one the novel proposed device is characterized by a compact size and an easy fabrication process. So that it will enable a convenient reduction of size, loss and cost in millimeter-wave and microwave systems.Keywords: Power Divider, HMSIW, SIW, CRLH-TL Cells, Tapered Transition

A miniaturized substrate-integrated waveguide (SIW) power divider with embedded filter response and arbitrary power-dividing ratio loaded by open complementary split-ring resonators (OCSRRs) is presented. In the proposed power divider, the miniaturization and filtering response are realized by a pair of OCSRRs, which are etched on the metal cover of the SIW structure. The design procedure indicates that the power division ratio can be adjusted by changing the locations of the output ports. In this study, three miniaturized filtering SIW power dividers with different power division ratios (1:1, 1:4, and 1:8) are implemented to evaluate the performance of the proposed structure on the size reduction. These power dividers (1:1, 1:4, and 1:8) have the overall sizes of 0.31λg× 0.14λg, 0.25λg× 0.17λg, and 0.25λg× 0.18λg, respectively. The measured results also agree well with the simulated results.

A novel Gysel power divider, which can be fabricated without a need for any high-impedance transmission-line section (TL), even for the power-division ratios higher than 15 dB, is presented. To derive its design formulas, a new study on the conventional in-phase T-junctions is carried out, and two conditions are newly derived for the arbitrary power-division ratios and perfect matching at all the ports, which can be applied for any symmetric or asymmetric Gysel power divider without any additional effort to design the isolation circuit. As a proof-of-concept demonstration, two prototypes I and II at the design frequency of 1 GHz are fabricated for the power-division ratios of 17 and 20 dB, respectively. Such power-division ratios have never been tried before not only for the Gysel power dividers but also for generic planar power divider topologies without the use of high-impedance TLs for the wider bandwidths. The measured results are in good agreement with the predictions.

In this letter, we present theoretical and experimental investigations of a rat-race coupler with negative group delay (NGD) characteristics and an arbitrary power division ratio. From the theoretical analysis, the NGD characteristics can be obtained through various transmission paths and have small variations with the power division ratio. The power division ratio is controlled by only the characteristic impedance of the transmission lines. Ideal port isolation and return loss characteristics are obtained at a center frequency for any arbitrary power division ratio. For experimental demonstration, a microstrip line rat-race coupler is implemented with center frequency of 2.14 GHz. The measurement results agree well with simulation results and theoretically predicated values.

A balanced-to-balanced Gysel power divider is proposed with bandpass filtering response and unequal power division. Design equations are provided for the proposed component, according to the power division ratio and filter specifications. Large design flexibility, small circuit size and low insertion loss can be achieved simultaneously. A microstrip prototype is developed at f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> =2 GHz with a second-order Chebyshev bandpass response. The bandwidth is 8% and the power division ratio of differential-mode outputs is 1:3. The phase difference is smaller than 5°. The suppression of in-band common-mode transmission and mode conversion is over 25 dB. Our idea is validated by the good agreement obtained between the measured and simulated results.

In this letter, compact substrate integrated waveguide (SIW) power dividers are presented. Both equal and unequal power divisions are considered. A quarter-wavelength long wedge shape SIW structure is used for the power division. Direct coaxial feed is used for the input port and SIW-tomicrostrip transitions are used for the output ports. Four-way equal, unequal and an eight-way equal division power dividers are presented. The four-way and the eight-way power dividers provide -10 dB input matching bandwidth of 39.3% and 13%, respectively, at the design frequency f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> = 2.4 GHz. The main advantage of the power dividers is their compact sizes. Including the microstrip to SIW transitions, size is reduced by at least 46% compared to other reported miniaturized SIW power dividers.

The substrate integrated waveguide (SIW) plays a very important role in millimetre-wave and microwave integrated circuits and systems with low return loss and high Q-factor. Also, the half-mode substrate integrated waveguide (HMSIW) has been developed in recent years. A new Y-junction four-way power divider is proposed by integrating the 90° Y-junction SIW power divider and HMSIW power divider. Simulated and measured results show that the return loss of the input port is below −15 dB over 8.6 to 12.2 GHz and transmissions are about −7.6 dB±0.2 dB in the passband. So, it makes the 6 dB power divider used preferably in a broad bandwidth. The new power divider can be produced in batches and can be widely used in millimetre-wave and microwave circuits owing to its simple and novel structure.

In this article, a new design for an equal and unequal dual-band Gysel power divider with a novel dual-band transformer has been proposed. This transformer is replaced with two conventional quarter-wavelength transmission lines between the isolation resistors. The proposed power divider thus has controllable bandwidth, exactly the same as the conventional Gysel power divider, as well as simple structure, wide frequency band ratio, good isolation and return loss, and high-power handling capability advantages over the Wilkinson power divider.

To satisfy the requirements of the emerging wireless communication system, the simultaneous implementation of large frequency ratio and tight coupling is demanded for a dual-band coupler. But most of the existing dual-band coupler structures can only achieve one of them. In this paper, a new coupled line based dual-band coupler structure is proposed. The detailed theoretical analysis is conducted for different ranges of frequency ratio. It was shown that a wide frequency ratio from 1.4 to 11.7 can be achieved even for the designs which require a tight coupling of 3 dB. For higher flexibility, the same circuit topology is further investigated to implement the arbitrary power division ratios over the two bands. More importantly, the design parameters for the large frequency ratio and arbitrary power division ratio are found to be almost independent resulting in a simple design procedure. For demonstration purposes, a dual-band 3 dB coupler with a large frequency ratio of 6 is designed, fabricated and measured. Furthermore, another dual-band coupler with coupling coefficients of 3 dB and 6 dB at 2 GHz and 4 GHz is designed, fabricated and measured. Good agreement between simulation and measurement can be observed for both prototypes.

An exact closed-form design approach for a generalized high-power n-way Gysel power divider is proposed. The power divider could be designed to achieve an arbitrary power ratio with the flexible multiway application, arbitrary real terminated impedance, excellent isolation, and easy fabrication through both planar and three-dimensional structures. Moreover, this improved power divider could maintain high power processing capacity through the coaxial cavity transmission line and grounding resistances. The exact analytical solutions related to ideal port matching and high isolation are obtained based on the circuit and transmission-line theory. To verify the proposed approach, a compact 3-way coaxial power divider with a pre-designed power ratio of 1:1.5:2 and four different real terminated impedances of 50, 55, 60, and 65 Ω is designed and fabricated. Excellent agreement is achieved between the simulated and measured results. Measurements from 4.7 to 5.7 GHz show that the return losses of all input and output ports are better than 15 dB. The maximum insertion loss is 0.5 dB, and the phase imbalance is approximately less than 6.1°. In addition, the isolation between any two output ports is better than 23 dB from 4.5 to 6 GHz. Meanwhile, the power handling capability can reach the maximum power of the commercial 50 Ω SMA connectors (2.098 kW).