Planar-circuit-type 3-dB quadrature hybrids

Kawai, Tadashi; Ohta, Isao

doi:10.1109/mwsym.1994.335335

Cited by 14 publications

(12 citation statements)

References 4 publications

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“…3 Multiple-input multiple-output (MIMO) antennas as the main part in wireless LTE systems have attracted the focus of many researches on their applications in both data transmission capacity and fading reduction. 4 In LTE and mobile phone applications, MIMO antennas can be used for enhancing data exchange speed and allowing a higher data transmission rate. In recent years, different types of microstrip MIMO antennas have been presented for LTE and mobile phone applications.…”

Section: Discussionmentioning

confidence: 99%

“…1,2 Standard PC realizations based on circular or rectangular geometries 1-5 exhibit limited bandwidth (BW)-defined in terms of power-split imbalance-which make them unsuitable for contemporary multi-or broad-band systems. Bandwidth enhancement can be obtained by means of appropriate topological modifications, including stubs, 2 slots, 2 impedance transformers, 6 stepped-impedance feeds (25% BW obtained in the study of Kawai and Ohta), 4 circular sections of different radii (22% BW achieved in the study of Zheng et al 3 ), or combinations thereof (eg, 35.9% BW obtained by using steppedimpedance feeds and ground plane slots). 6 A disadvantage of the aforementioned designs is manually preselected (thus, fixed) topology of the coupler which, on one hand, makes the design problem easier, but also limits opportunities for performance improvements.…”

Section: Introductionmentioning

confidence: 99%

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Novel structure and design of enhanced‐bandwidth hybrid quadrature patch coupler

Bekasiewicz

Koziel

2018

Micro & Optical Tech Letters

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A novel structure and design optimization procedure of an enhanced-bandwidth hybrid quadrature patch coupler is proposed. Improved performance of the circuit has been obtained by parameterizing the coupler sections using splines, which introduces additional degrees of freedom. Due to computational complexity of the parameter adjustment problem, a sequential design procedure is applied. In each iteration, a selected number of spline control points is used and their radial coordinates are optimized. The design found this way is then used as a starting point for the next iteration with an increased number of spline control points. The final design parameterized by 20 control points exhibits over 50% bandwidth at the operational frequency of 10 GHz, and acceptable footprint of 13.8 mm × 15.7 mm. K E Y W O R D Scomputer-aided design, design optimization, EM-driven design, patch couplers, topology evolution

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Novel structure and design of enhanced‐bandwidth hybrid quadrature patch coupler

Bekasiewicz

Koziel

2018

Micro & Optical Tech Letters

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“…Such structures can be grouped into three categories, namely patches [128][129][130][131], sector components [59,60,[132][133][134][135] and rings [136] (resembling the hybrid ring). Such structures can be grouped into three categories, namely patches [128][129][130][131], sector components [59,60,[132][133][134][135] and rings [136] (resembling the hybrid ring).…”

Section: Resonating Planar Combinersmentioning

confidence: 99%

Power Combining

general

2009

High Efficiency RF and Microwave Solid State Power Amplifiers

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Power amplifiers are employed in a variety of system applications, where the required power levels are largely different, varying from mW to kW [1,2]. Consequently, a wide variety of PA realizations results, from travelling-wave tube amplifiers in very high power systems [3,4], in satellite payloads or radars, to solid-state amplifiers for medium-low power systems [5,6], such as wireless communication handsets. The request for high output power levels is influencing device technologies adopted for PA module realization [7,8]. Prior to the development of solid state devices, microwave power amplification and generation were mainly based on the use of vacuum tubes [9, 10], including magnetron, klystron and travelling-wave implementations (TWTAs) [4,11]. These devices still remain in use at kilowatt levels, where solid-state devices cannot compete so far.Nevertheless, the development of high power microwave solid-state device technologies (GaAs HEMT or HBT, GaN HEMT, etc.) may offer an order-of-magnitude improvement in reliability and reduction in size, weight, and low-voltage power-supply requirements as compared to vacuum devices. However, the output power attainable from a single solid-state device is basically limited by thermal and impedance matching problems. To meet system requirements it is therefore mandatory to combine several devices, thus attaining higher power levels. Many power splitting/combining schemes have been investigated and developed, involving different technologies and propagation media, ranging from metal waveguides (cavities, microstrips, striplines, etc.) where the power is confined into a limited region, to open space configurations [12][13][14].Devices involved in power splitting/combining operations are referred to as power splitters/ combiners and they play a key role in the design of high power PA, while being also fundamental components in designing mixers [15], multipliers and oscillators [16,17], or other linear and nonlinear circuits [18]. Moreover, since the proposed schemes can often be adopted for both the tasks of power division and combination, the terms power combining and power splitting are usually adopted simultaneously or interchangeably. Due to their intrinsic reciprocal characteristic in fact, the same device can alternatively be viewed as a power combiner or as a power splitter, depending on the selection of its input and output ports.The key features of power splitting/combining devices are clearly their insertion loss (related to the efficiency), bandwidth and size. The techniques adopted for the optimization of device performance are strictly related to the type of splitting/combining structure and to the selected realization technology. High Efficiency RF and Microwave Solid State Power Amplifiers

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“…Nevertheless, it was found in [Z, 31, that a rectangulardisc coupler with additional convexes or concaves in its shape, can produce an operational bandwidth similar to that of a standard branch-line coupler. In addition, in [3] and [4] it was realized that a further increase in operational bandwidth can be obtained by adding new elements, which include impedance steps and tuning stubs. The idea of using circular or rectangular discs with impedance steps and stubs for the design of 180" hybrids has already been explored in [S-71.…”

Section: Introductionmentioning

confidence: 99%

“…Also, using a similar approach as in [S-7], 3-dB 90" hybrids with very flat coupling and excellent matching and isolation characteristics over a 20% bandwidth have been demonstrated in [3, 41. Triplate technology in [3] and microstrip technology in [4] was used to develop the quadrature devices with increased operational bandwidth. Other differences between the work performed in [3] and [4] included the values of the impedance steps.…”

Section: Introductionmentioning

confidence: 99%