Wideband planar log-periodic balun

Basraoui, M.; Shastry, Prasad N.

doi:10.1002/mmce.1043

Cited by 11 publications

(15 citation statements)

References 6 publications

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“…Distributed-TL designs are inherently narrowband due to the frequency dependence of the TLs used. These can be made broadband; however, they usually require transmission lines that are at least several wavelengths long and are therefore not very compact [61]. Lumped-element designs, albeit compact, can suffer from a relatively narrowband differential output phase resulting from the inherent mismatch between the phase response of the lowpass/highpass output lines that they employ [62].…”

Section: A Broadband Wilkinson Balun Using Microstrip Nri-tl Metamatementioning

confidence: 99%

Antenna Applications of Negative Refractive Index Transmission‐Line (NRI‐TL) Metamaterials

Eleftheriades¹,

Antoniades²

2007

Modern Antenna Handbook

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In the 1960s Victor Veselago systematically examined hypothetical materials having simultaneously negative permittivity and negative permeability [1]. He described a number of unusual electromagnetic phenomena associated with such media. A characteristic property of these materials is that plane waves propagating in them would have their phase velocity antiparallel to the group velocity; hence these media would support backward waves. Likewise, the vectors describing the electric field, the magnetic field, and the propagation direction would follow the left-handed rule. For this latter reason, Veselago coined the term "left-handed" to describe these hypothetical media. Moreover, he associated this kind of "left-handedness" with the notion of negative refraction and he described several unusual focusing devices (e.g., lenses) based on negative refraction. Nevertheless, it should be pointed out that the notion of negative refraction at the interface between a normal dielectric and a dielectric supporting backward waves had been described as early as the beginning of the 20th century [2,3]. It was only recently though that people devised methods of implementing these left-handed or negative refractive index (NRI) media. The first such implementation was produced at the University of California in San Diego and comprised a volumetric periodic array of straight metallic wires and split-ring resonators to synthesize negative effective permittivity and negative effective permeability, respectively, at microwave frequencies [4,5].Another way to implement artificial materials (metamaterials) that support the phenomenon of negative refraction was subsequently proposed based on the concept of loading planar transmission-line grids with reactive elements (see subsequent sections). This transmission-line (TL) approach does not rely on loosely coupled resonators to synthesize the negative permeability; rather, it depends on the electrical connections between the constituent NRI-TL unit cells to create tightly coupled resonators, thus leading to large bandwidths over which the refractive index remains negative. The explicit formulation of Modern Antenna Handbook. Edited by Constantine A. Balanis

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Section: A Broadband Wilkinson Balun Using Microstrip Nri-tl Metamatementioning

confidence: 99%

Antenna Applications of Negative Refractive Index Transmission‐Line (NRI‐TL) Metamaterials

Eleftheriades¹,

Antoniades²

2007

Modern Antenna Handbook

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“…Test result shows nearly 1.5 dB flat leakage over the input power range of 15 dB and the threshold power adjustment of nearly 15 dB by bias voltage adjustment. Limiter circuits are used to protect sensitive devices used in receivers and SSPAs from intentionally or unintentionally exposure of high-power level [1][2][3]. Though, p-i-n diodes have superior performance as limiter, Schottky diode limiters are better choice for its suitability in MMIC technology [4,5].…”

Section: Received 23 September 2009mentioning

confidence: 99%

“…The technique combines the attractions of fiber lasers with high-power multimode-diode pumping and leads to fiber laser with high-power and high-quality output, even when low-brightness diode lasers are used pump sources. Being benefited from large mode area (LMA) fibers and the technique of pump coupling, the output power from ytterbiumdoped fiber lasers have grown dramatically and exceeded kilowatt levels (e.g., 1.36 kW [1], 2.5 kW [2]). In 2008, the output power of 6 kW from a single fiber is obtained with excellent quality by IPG Photonics Corporation [3].…”

Section: Introductionmentioning

confidence: 99%

1.75-Kilowatt continuous-wave output fiber laser using homemade ytterbium-doped large-core fiber

Zhou

Lou

et al. 2010

Microw. Opt. Technol. Lett.

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À3.43 dB) and À3.43 dB (À3.2 dB), respectively. The maximum value of amplitude unbalance, the difference in power of S 31 and S 21 between two output ports, is measured (simulated) at 0.7 dB (0.35 dB) in the operating band. Figure 7 shows the simulated and measured phase differences between two output ports. The simulated phase differences between two output ports of a conventional MSL Wilkinson balun are compared. The conventional MSL Wilkinson balun are designed using two branches of À90 and À270 phase shift MSL. The differential output phase is shown to be flat in the operation band of the proposed balun. The fractional 180 6 10 bandwidth of the balun based on the PLH TL is measured (simulated) at 71% (70%) from 1.47 GHz (1.44 GHz) to 3.09 GHz (2.99 GHz), whereas the bandwidth of the conventional MSL balun is only 10.8% from 2.36 GHz to 2.63 GHz. Consequently, the broadband Wilkinson balun based on a PLH TL has good properties, such as return loss, isolation, and through in the broad frequency range.Furthermore, a wideband balun based on modified PLH TL [6] having a wide LH bandwidth is designed by the full wave simulation. The illustration of Figure 7 shows the top view of the modified PLH TL. The other dimensions of modified PLH TL are exactly the same with those of Figure 1 except for dimensions in figure caption of Figure 7. In this case, to satisfy the Eq. (4), the lengths of L 1 and L 2 are determined as 20.8 mm (corresponding to 4-stage modified PLH TL) and 60.3 mm, respectively. The designed balun has the fractional bandwidth of 107.8% from 1.12GHz to 3.74GHz, as shown in Figure 7. Consequently, the PLH TL balun is well-suited for RF devices requiring a broadband balanced signal. CONCLUSIONS ABSTRACT:We have demonstrated a homemade high-efficient ytterbium-doped fiber laser with up to 1.75 kW of continuous-wave output power at 1.09 lm with a slope efficiency of 76%. The fiber is pumped by two laser diode array (LDA) sources launched through opposite ends. No undesirable effect is observed with increasing pump power, which suggests that the homemade fiber laser could produce higher power output by using more pump sources.

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“…Somehow, baluns are still regarded as a kind of magic by some engineers and studied in recently years. Due to its wide bandwidth and inherent amplitude with ISO-degree phase balance, many different structured baluns such as log periodic balun [14], three line balun [15], N section half wave balun [16J, microstrip taper balun [17] and lump balun [1SJ are adroitly applied in microwave circuits. Balun is a circuit that transform from unbalance to balance or balance to unbalance.…”

Section: Introductionmentioning

confidence: 99%

“…Active balun [12][13][14][15] are constructed by active element (FET) with common source transistor or common gate transistor to achieve impedance match. Generally, an active balun has its output gain that can decrease an oscillator's input gain for mixer applications.…”

Section: Introductionmentioning

confidence: 99%

Design of a planar balun

Sun

Lee²

APMC 2001. 2001 Asia-Pacific Microwave Conference (Cat. No.01TH8577)

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Innovation of the Marchand balun model is presented. The structure of the designed planar micro strip matching circuit is fairly simple, practical and easily fabricated without requiring complex multiple metal or dielectric layers. Moreover, the designed balun performs well. The measured phase difference between balance ports was within 1800 ± 3° from 1.9GHz to 3.9GHz and results of S2l and S3l are fairly close to -3dB from 2.4GHz to 3.2GHz. Design and simulation of a planar microstrip balun with its measured results show good agreements with those simulated data.

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Wideband planar log-periodic balun

Cited by 11 publications

References 6 publications

Antenna Applications of Negative Refractive Index Transmission‐Line (NRI‐TL) Metamaterials

Antenna Applications of Negative Refractive Index Transmission‐Line (NRI‐TL) Metamaterials

1.75-Kilowatt continuous-wave output fiber laser using homemade ytterbium-doped large-core fiber

Design of a planar balun

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