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1. |
Record Nr. |
UNINA9910160669903321 |
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Autore |
Abdelrahman Ahmed H. |
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Titolo |
Analysis and design of transmitarray antennas / / Ahmed H. Abdelrahman, Fan Yang, Atef Z. Elsherbeni, Payam Nayeri |
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Pubbl/distr/stampa |
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[San Rafael, California] : , : Morgan & Claypool, , 2017 |
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ISBN |
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Descrizione fisica |
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1 online resource (177 pages) : color illustrations |
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Collana |
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Synthesis lectures on antennas, , 1932-6084 ; ; # 12 |
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Disciplina |
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Soggetti |
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Antenna arrays |
Transmitting antennas |
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Lingua di pubblicazione |
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Formato |
Materiale a stampa |
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Livello bibliografico |
Monografia |
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Note generali |
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Part of: Synthesis digital library of engineering and computer science. |
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Nota di bibliografia |
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Includes bibliographical references (pages 141-145). |
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Nota di contenuto |
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1. Introduction -- 1.1 Transmitarray antenna concept -- 1.2 Comparison with some related antenna technologies -- 1.3 Transmitarray design approaches -- 1.3.1 Multi-layer frequency selective surfaces (M-FSS) -- 1.3.2 Receiver-transmitter design -- 1.3.3 Metamaterial/transformation approach -- 1.4 Overview of research topics -- |
2. Space-fed array design method -- 2.1 Phase distribution on transmitarray aperture -- 2.2 Unit-cell element analysis -- 2.3 Radiation analysis using the array theory -- 2.4 Directivity calculations -- 2.4.1 Method 1: numerical integration -- 2.4.2 Method 2: utilization of Bessel function -- 2.4.3 Method 3: illumination efficiency -- 2.4.4 Comparison between the three methods -- 2.4.5 Directivity bandwidth -- 2.5 Antenna gain -- 2.5.1 Spillover efficiency -- 2.5.2 Element losses -- 2.6 Phase error analysis -- 2.6.1 Design errors -- 2.6.2 Approximations in unit-cell analysis -- 2.6.3 Manufacturing errors -- |
3. Analysis of multi-layer transmitarray antenna -- 3.1 Single-layer FSS analysis -- 3.1.1 Theoretical analysis of single-layer FSS -- 3.1.2 Numerical demonstration of single-layer FSS -- 3.1.3 Single-layer of double square loop elements -- 3.1.4 Single conductor with a substrate layer -- 3.2 Double-layer FSS analysis -- 3.2.1 Theoretical analysis of double-layer FSS -- 3.2.2 Numerical demonstration of double-layer FSS -- 3.3 Multi-layer FSS analysis -- 3.3.1 Analytical analysis of triple-layer FSS -- 3.3.2 Numerical demonstration of triple-layer FSS -- 3.3.3 |
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Quad-layer FSS -- |
4. A quad-layer transmitarray antenna using slot-type elements -- 4.1 Cross-slot transmitarray antenna design -- 4.1.1 Cross-slot element design -- 4.1.2 Transmitarray design and measurements -- 4.2 Discussion on oblique incidence and feed polarization effects -- 4.2.1 Element performance under oblique incidence -- 4.2.2 Aperture distribution and radiation pattern -- |
5. Design of triple-layer transmitarray antennas -- 5.1 Identical triple-layer transmitarray antenna -- 5.1.1 Spiral dipole element design -- 5.1.2 Transmitarray design -- 5.1.3 Experiment and discussion -- 5.2 Non-identical triple-layer transmitarray antenna -- 5.2.1 Non-identical double-layer FSS analysis -- 5.2.2 Non-identical triple-layer FSS analysis -- 5.3 Double-layer unit-cells -- |
6. Wideband transmitarray antennas -- 6.1 Bandwidth analysis of a transmitarray using quad-layer double square loop elements -- 6.1.1 Unit-cell property -- 6.1.2 Bandwidth performance of transmitarray -- 6.2 Bandwidth performance with different reference phases at the aperture center -- 6.3 Proper selection of element phase range for improvement of transmitarray bandwidth -- 6.4 Comparison between different element shapes -- 6.5 Prototype fabrication and measurements -- |
7. Single-feed multi-beam transmitarrays -- 7.1 Design methodologies for single-feed multi-beam transmitarray antennas -- 7.2 Design of Ku-band single-feed quad-beam transmitarray antennas -- 7.3 Prototype fabrication and measurements -- 7.4 Transmitarray approximation and performance discussions -- 7.4.1 Oblique incidence effect of the unit-cell element -- 7.4.2 Variations in dimensions of neighboring elements -- 7.4.3 Phase error and magnitude loss effect on the radiation patterns -- |
8. Conclusions -- 8.1 Contributions of this book -- 8.2 Future work -- A. S-matrix of cascaded layers -- Bibliography -- Authors' biographies. |
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Sommario/riassunto |
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In recent years, transmitarray antennas have attracted growing interest with many antenna researchers. Transmitarrays combines both optical and antenna array theory, leading to a low profile design with high gain, high radiation efficiency, and versatile radiation performance for many wireless communication systems. In this book, comprehensive analysis, new methodologies, and novel designs of transmitarray antennas are presented. |
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2. |
Record Nr. |
UNINA9910760255703321 |
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Autore |
Fuentes Marcelo E |
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Titolo |
Contradictory Muslims in the Literature of Medieval Iberian Christians / / by Marcelo E. Fuentes |
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Pubbl/distr/stampa |
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Cham : , : Springer Nature Switzerland : , : Imprint : Palgrave Macmillan, , 2024 |
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ISBN |
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Edizione |
[1st ed. 2024.] |
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Descrizione fisica |
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1 online resource (234 pages) |
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Collana |
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The New Middle Ages, , 2945-5944 |
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Disciplina |
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Soggetti |
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Literature, Medieval |
Europe - History - 476-1492 |
Religion - History |
Islam - Study and teaching |
Philosophy, Medieval |
Medieval Literature |
History of Medieval Europe |
History of Religion |
Islamic Studies |
Medieval Philosophy |
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Lingua di pubblicazione |
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Formato |
Materiale a stampa |
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Livello bibliografico |
Monografia |
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Nota di contenuto |
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Chapter 1. Introduction. Friendly Chivalrous Enemies: Contradiction, Stereotypes, and Colonialism in the Representations of Muslims by Medieval Christians -- Chapter 2. Indispensable Enemies, Subjects, and Friends: The Political Instrumentalization of Muslims in the Cantar de mio Cid -- Chapter 3. The Learned Conquerors and Their Muslims: Intercultural Conflict and Collaboration in the Cantigas de Santa Maria and the Llibre dels fets -- Chapter 4. From Great Muslim Heroes to Good Christian Subjects: Converting the Legend of the Seven Infantes of Lara -- Chapter 5. Across the Mediterranean and Beyond: Fighting Islam by Embracing Muslims in Tirant lo Blanch -- Chapter 6. An Empire of Faith and Its Infidels: Portuguese Colonialism and Muslims, According to Os Lusíadas and Its Sources -- Chapter 7. Conclusion. |
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Christian Supremacy and Contradictory Non-Christians Beyond Muslims and Iberia. |
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Sommario/riassunto |
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This book argues that literary and historiographical works written by Iberian Christians between the twelfth and sixteenth centuries promoted contradictory representations of Muslims in order to advocate for their colonization through the affirmation of Christian supremacy. Ambivalent depictions of cultural difference are essential for colonizers to promote their own superiority, as explained by postcolonial critics and observed in medieval and early modern texts in Castilian, Catalan, and Portuguese, such as the Cantar de mio Cid, Cantigas de Santa Maria, Llibre dels fets, Estoria de España, Crónica geral de 1344, Tirant lo Blanch, and Os Lusíadas. In all these works, the contradictions of Muslim enemies, allies, and subjects allow Christian leaders to prevail and profit through their opposition and collaboration with them. Such colonial dynamics of simultaneous belligerence and assimilation determined the ways in which Portugal, Spain, and later European powers interacted with non-Christians in Africa, Asia, and even the Americas. |
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