Impedance Network for an Automatic Impedance Matching System

Brito, Karolinne; Lima, Robson Nunes de

doi:10.1109/apmc.2007.4554608

Cited by 11 publications

(3 citation statements)

References 11 publications

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“…The Central Committee selected Armando Guebuza, a member of the "historic generation," as Frelimo's presidential candidate, and the party quickly rallied behind Guebuza. 159 Thanks in part to a growing economy, Frelimo won the 2004 elections easily. In 2009, Guebuza was re-elected in a landslide, leading Africa Confidential to observe that "Frelimo's grip over the country is now total."…”

Section: Mozambiquementioning

confidence: 99%

Beyond Patronage: Violent Struggle, Ruling Party Cohesion, and Authoritarian Durability

2012

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We explore the sources of durability of party-based authoritarian regimes in the face of crisis. Recent scholarship on authoritarianism suggests that ruling parties enhance elite cohesion—and consequently, regime durability—by providing institutionalized access the spoils of power. We argue, by contrast, that while elite access to power and spoils may ensure elite cooperation during normal times, it often fails to do so during crises. Instead, the identities, norms, and organizational structures forged during periods of sustained, violent, and ideologically-driven conflict are a critical source of cohesion—and durability—in party-based authoritarian regimes. Origins in violent conflict raise the cost of defection and provide leaders with additional (non-material) resources that can be critical to maintaining unity and discipline, even when a crisis threatens the party's hold on power. Hence, where ruling parties combine mechanisms of patronage distribution with the strong identities, solidarity ties, and discipline generated by violent origins, regimes should be most durable.We apply this argument to four party-based competitive authoritarian regimes in post-Cold War Africa: Kenya, Mozambique, Zambia, and Zimbabwe. In each of these cases, an established single- or dominant-party regime faced heightened international pressure, economic crisis, and a strong opposition challenge after 1990. Yet whereas ruling parties in Kenya and Zambia were organized almost exclusively around patronage, those in Mozambique and Zimbabwe were liberation parties that came to power via violent struggle. This difference is critical to explaining diverging post-Cold War regime outcomes: whereas ruling parties in Zambia and Kenya imploded and eventually lost power in these face of crises, those in Mozambique and Zimbabwe remained intact and regimes survived.

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Section: Mozambiquementioning

confidence: 99%

Beyond Patronage: Violent Struggle, Ruling Party Cohesion, and Authoritarian Durability

2012

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“…Due to the bilinear nature of impedance transformations of switchable matching networks, circles described by (3) and (4) can be mapped onto circles centered at the origin of the Smith chart with radius max Zin Γ . Using many suitably positioned circles a whole band can be constructed, directly outside the circles with radius max Zin Γ that can be mapped onto the center circle [22,23], see Fig. 3.…”

Section: B Single Ring Impedance Matchingmentioning

confidence: 99%

“…This paper presents a mathematical estimation of the minimum required number of states for narrow band switchable matching networks to match a certain load impedance range to within a smaller input impedance range. This problem was implicitly addressed in [22]- [24] for specific implementations, without giving a general approach or mathematical derivation.…”

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confidence: 99%

On the Minimum Number of States for Switchable Matching Networks

Firrao

Annema

Vliet

et al. 2015

IEEE Trans. Circuits Syst. I

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The impedance of an antenna changes heavily with changing EM environments, while RF power amplifiers (PAs) are optimized for driving a well-defined load impedance. As a solution, switchable matching networks are used in automatic antenna tuners to match the antenna impedance to (about) the desired PA load impedance. This paper presents a theoretical treaty of the minimum number of required states for switchable matching networks to achieve sufficient matching from a certain load VSWR to a sufficiently low input VSWR. First for an arbitrary passive lossless switchable matching network, the mathematical minimum required number of states as a function of the required input VSWR and of the required load VSWR is derived. Several variants are analyzed and benchmarked: single-stage one-ring configuration, single-stage two-ring configuration, two-stage one-ring configuration and threestage one-ring configuration showing that single-ring configurations are optimum. An extension towards the required number of states for lossy matching networks is also provided.

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Matching Network Tuning and Control Methods

2014

RF Tunable Devices and Subsystems: Methods of Modeling, Analysis, and Applications

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Impedance Network for an Automatic Impedance Matching System

Cited by 11 publications

References 11 publications

Beyond Patronage: Violent Struggle, Ruling Party Cohesion, and Authoritarian Durability

Beyond Patronage: Violent Struggle, Ruling Party Cohesion, and Authoritarian Durability

On the Minimum Number of States for Switchable Matching Networks

Matching Network Tuning and Control Methods

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