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"This single volume provides a comprehensive introduction and explanation of both the theory and practice of 'Planar Near-Field Antenna Measurements', from its basic postulates and assumptions, to the intricacies of its deployment in complex and demanding measurement scenarios. To do this the book initially examines the properties of antennas that allow them to enhance the free space interaction of electronic systems and this leads into a full description of the theory of 'Planar Near-Field Scanning'."

"Teknologi nirkabel sangat berkembang sekarang ini dan salah satu elemen terpenting adalah antena. Pada umumnya antena di sisi pengguna berdimensi kecil dan diharapkan memiliki nilai gain tinggi. Dengan menggunakan struktur High Impedance Surface (HIS) sebagai substrat maka gain dapat meningkat tanpa menambahkan dimensi antena. Pada penelitian ini, struktur HIS berbentuk planar rectangular diimplementasikan sebagai substrat antena mikrostrip dengan dua feedline yang bekerja di frekuensi 2,445 GHz dengan bandwidth 85 MHz. Unit cell HIS dirancang dan disimulasikan untuk melihat daerah frekuensi kerja dengan memperhatikan reflection phase diagram. Unit cell dengan susunan 1x2 elemen diimplementasikan pada antena mikrostrip patch lingkaran yang dicatu dengan teknik elektromagnetik kopel. Antena ini terdiri dari dua lapisan substrat. Lapisan pertama terdiri dari patch berbentuk lingkaran dan lapisan kedua terdiri dari dua feeding line bersama unit cell HIS. Hasil simulasi menunjukan di port 1 bandwidth bernilai 150 MHz dan gain sebesar 7,85 dB. Untuk port 2, menunjukan bandwidth 160 MHz dan gain 7,98 dB. Pengukuran dilakukan dan menunjukan hasil untuk port 1 memiliki bandwidth 160 MHz dan gain 7,92 dB. Sedangkan untuk port 2, bandwidth bernilai 170 MHz dan gain sebesar 7,12 dB.

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Wireless technology is developing nowadays and one of the most important elements in wireless technology is the antenna. For the user, antenna usually has compact size and considers having high gain. By using High Impedance Surface structure as the substrate, it can enhance gain performance without increase dimension of antenna.

In this research, planar rectangular HIS structure has been implemented as substrate of microstrip antenna with dual feeding line. The resonant frequency is 2,445 GHz with 85 MHz bandwidth. HIS unit cell is designed and simulated to obtain the resonant frequency as shown in its reflection phase diagram. The unit cell consists of 1x2 planar array configuration is implemented in circular patch microstrip antenna using electromagnetic coupled feeding method. The antenna consists of two substrate layers. The first layer consists of circular patch and the second substrate consists of two feed lines with HIS unit cell.

Based on simulation results, in port 1 shows bandwidth of 150 MHz and 7,85 dB gain. For port 2, the bandwidth is 160 MHz with 7,98 dB gain. To validate the simulation result, measurement has been conducted. Measurement results show 160 MHz bandwidth and 7,92 dB gain in port 1, meanwhile, in port 2, shows 170 MHz bandwidth and 7,12 dB gain."

"Perkembangan teknologi komunikasi bergerak menuntut dimensi perangkat yang kecil, tipis, dan ringan. Untuk menjawab tuntutan tersebut, digunakan antena planar. Masalah utama dalam desain antena planar adalah timbulnya gelombang permukaan dalam material substrat yang mengakibatkan penurunan karakteristik radiasi. Salah satu cara mengeleminasi gelombang permukaan adalah penggunaan struktur μ negative (MNG) metamaterial spiral resonator (SR). Oleh karena itu dilakukan studi antena planar struktur spiral resonator (SR) sebagai elemen radiator untuk mencari sifat μ negative (MNG) metamaterial-nya pada rentang frekuensi hingga 5 GHz, mengembangkan model pendekatan analitis untuk mengkarakteristik pola radiasi, melakukan simulasi dan pengukuran karakteristik radiasi pada frekuensi 2,4 GHz. Hasil studi antena planar struktur MNG metamaterial SR menunjukkan bahwa permeabilitas efektif (μeff) mempunyai bagian riil negatif ?2,5 pada frekuensi paling rendah 0,1 GHz, relatif tidak berubah terhadap perubahan nilai N = 3, 5, 7, dan 10. Bagian imajiner negatif menunjukkan kecenderungan frekuensi bergeser ke kiri dengan bertambah besarnya nilai N. Sedangkan nilai permitivitas efektif (eff) positif untuk semua rentang frekuensi, kecuali rentang frekuensi 0,1 ? 0,7 GHz berharga negatif. Hal ini menunjukkan bahwa nilai negatif μeff dan nilai positif eff merupakan sifat MNG struktur SR pada rentang frekuensi tersebut. Perbandingan hasil simulasi dan perhitungan permeabilitas efektif (μeff) dan permitivitas efektif (eff) menunjukkan kemiripan karakteristik. Selain melalui simulasi dan pengukuran, karakteristik pola radiasi diperoleh melalui pendekatan linier susun (linear array approach) untuk struktur SR patch tunggal dan pendekatan planar susun (planar array approach) untuk struktur SR patch susun. Perbandingan karakteristik pola radiasi hasil simulasi, pengukuran, dan pendekatan linier susun atau pendekatan planar susun menunjukkan kesamaan pada arah boresight, meskipun terjadi sedikit perbedaan pada sidelobe dan backlobe. Dengan demikian model pendekatan analitis ini dapat digunakan sebagai metode alternatif untuk mengkarakteristik pola radiasi antena planar struktur MNG metamaterial SR. Hasil simulasi dan pengukuran karakteristik radiasi antena yang distudi menunjukkan kemiripan dengan perolehan frekuensi 2,41 GH, S11 = ?23 dB, bandwidth hingga 96 MHz pada S11 = ?10 dB, gain antena = 6,8 dB dan efisiensi hingga 73,4%. Dimensi antena yang diusulkan berkurang hingga 53 % dibanding dengan antena patch konvensional. Spiral Resonator (SR) mempunyai struktur yang unik, dapat berfungsi sebagai radiator dan secara signifikan dapat mereduksi dimensi antena planar. Oleh karena itu, struktur SR memiliki prospek yang baik untuk pengembangan aplikasi antena planar.

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The development of mobile communications technology requires the device to be small, thin, and light weight. To solve this requirement, the planar antenna is used. The main problem in the design of planar antenna is the emergence of surface waves in the substrate material that reduce the radiation characteristics. To eleminate the surface wave, the μ negative (MNG) metamaterial spiral resonator (SR) is used. Therefore, the study of planar antenna with SR structure as a radiator elemen is conducted to search its μ negative (MNG) metamaterial at the frequency range up to 5 GHz, to develop a model of the analytical approach for characterizing a radiation pattern, to simulate and measure radiation characteristics at the frequency of 2.4 GHz.

The result of the study of the planar antenna with μ negative (MNG) metamaterial SR structure shows that effective permeability value has a negative real part of ?2.5 along the frequency at least 0.1 GHz, which is relatively change to the N value such as N = 3, 5, 7, and 10. Its imaginary part shows the frequency tend to move left if N value increase. The effective permittivity is positive for the frequency range of 0 ? 5 GHz, except for the frequency range of 0.1 ? 0.7 GHz is a negative. It shows that the negative value of μeff and positive value of eff indicate the MNG properties of the SR structure at the frequency range. Comparison between simulation and calculation results of the effective permeability and permittivity shows a good agreement.

In addition through simulation and measurement, the radiation pattern can be characterized by linear array approach for single patch SR structure and planar array approach for patch array SR structure. Comparison among of the simulation, measurement, and linear array approach for single patch SR structure and planar array approach for patch array SR structure shows a good agreement at a boresight direction, even though there was a slight difference at the sidelobe and backlobe. It shows that this analytical model can be used as alternative method to characterize the radiation pattern of the planar antenna with μ negative (MNG) metamaterial SR structure.

The simulation and measurement results of the radiation characteristic of the proposed antenna show a good agreement such as the frequency of 2.41 GHz, S11 = ?23 dB, bandwidth up to 96 MHz at S11 = ?10 dB, antenna gain = 6.8 dB and efficiency up to 73.4%.

Spiral resonator (SR) has a unique structure, it can be functionalized as a radiator and significantly reduce the dimension of the planar antenna. Therefore, the SR structure has a good prospect for developing of the planar antenna aplication."

""Stutzman's 3rd edition of Antenna Theory and Design provides a more pedagogical approach with a greater emphasis on computational methods. New features include additional modern material to make the text more exciting and relevant to practicing engineers; new chapters on systems, low-profile elements and base station antennas; organizational changes to improve understanding; more details to selected important topics such as microstrip antennas and arrays; and expanded measurements topic"--"

"Skripsi ini membahas rancang bangun antena reconfigurable untuk aplikasi cognitive radio pada alokasi spektrum 1,8 GHz, 2,1 GHz uplink, 2,1 GHz downlink, dan 2,35 GHz. Rancang bangun antena terdiri dari dua antena yaitu antena sensing dan antena communicating yang digabungkan dalam satu divais. Antena sensing memiliki karakteristik ultrawideband dari 1,65 GHz - 3,75 GHz (bandwidth = 2,1 GHz) dan antena communicating memiliki karakteristik narrowband pada frekuensi 1.8 GHz, 2.1 GHz uplink, 2.1 GHz downlink, dan 2.35 GHz. Hasil validasi dengan pengukuran diperoleh hasil yang sesuai dengan rancangan simulasi, terutama meliputi parameter return loss, pola radiasi, dan gain.

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This bachelor thesis discusses a design and fabrication of reconfigurable antenna for cognitive radio applications, especially for allocation of spectrum 1.8 GHz, 2.1 GHz Uplink, 2.1 GHz Downlink, and 2.35 GHz. The antenna design consists of two antennas which sensing antenna and communicating antenna. The sensing antenna has ultrawideband characteristics from 1.65 GHz - 3.75 GHz (the bandwidth about 2.1 GHz) and the communicating antenna has narrowband characteristics at the center frequency 1.8 GHz, 2.1 GHz uplink, 2.1 GHz downlink, and 2.35 GHz. The validation has been conducted by the measurement, where it agrees with the simulation result, in particular for the parameter of return loss, radiation pattern and gain of the antenna."