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Abstrak :
Kebutuhan akan antena berdimensi kecil namun memiliki performa yang tinggi mendorong berbagai riset untuk melakukan eksperimen tidak hanya dari sisi struktur dan bentuk antena tetapi juga dari sisi material. Pemanfaatan karakteristik magneto-dielektrik baik secara buatan maupun hasil rekayasa material sebagai pereduksi dimensi dan peningkat performa antena diusulkan pada penelitian ini. Karakteristik MD direalisasikan melalui struktur SRR susun sebagai peningkat performa antena; dan sintesis material sebagai pereduksi dimensi antena. Studi parametrik dan eksperimen dilakukan untuk mendapatkan dimensi SRR serta konfigurasi SRR yang paling optimal sehingga diperoleh pengaruh yang dapat meningkatkan performa antena. Bahan MD telah berhasil disintesis dari campuran serbuk magnetit (Fe3O4) nanopartikel sebagai bahan magnetik, bahan polimer elastis PDMS (polydimethylsiloxane) sebagai bahan dielektrik, dan BaFe12O19 sebagai bahan tambahan untuk membantu daya rekatnya dengan host dielectric. Bahan MD ini telah berhasil dikarakterisasi baik dari sisi material maupun kelistrikannya. Berdasarkan hasil karakerisasi material dari uji XRD, SEM, dan VSM diketahui bahwa campuran terdispersi secara merata dan memiliki sifat magnetik yang baik. Sedangkan berdasarkan hasil karakterisasi kelistrikan melalui pengukuran dengan waveguide dan sensor diketahui bahwa penambahan komposisi magnetit dalam sampel dapat meningkatkan permitivitas dan permeabilitas relatif bahan. Hasil karakterisasi material dan elektrikal kemudian disimulasikan untuk merancang antena mikrostrip kombinasi antara substrat dari bahan MD dan struktur SRR. Antena mikrostrip ini tersusun dari dua bagian yaitu patch pada bahan MD dan struktur SRR susun pada bahan dielektrik sebagai groundplane antena. Kedua bagian ini disusun secara berlapis menjadi satu kesatuan antena mikrostrip. Hasil studi parametrik menunjukkan antena yang dirancang pada bahan sampel C (rasio PDMS : Fe3O4 = 1 : 0,6) dengan konfigurasi SRR 3 × 3 pada bahan dielektrik (εrHost < εrMD) memberi respon yang paling optimal. Kondisi optimal ditentukan atas pertimbangan trade off yang terjadi dari masing-masing variasi pada aspek reduksi dimensi antena dan performa antena. Penelitian ini telah berhasil menemukan metode untuk memperoleh antena dengan dimensi yang lebih kecil dengan performa yang lebih tinggi dibanding antena tanpa bahan MD dan struktur SRR. Sebagai perbandingan, analisis yang sama juga dilakukan pada frekuensi yang sama untuk antena mikrostrip konvensional (tanpa bahan MD dan struktur SRR), antena mikrostrip dengan struktur SRR tanpa bahan MD, serta antena berbahan MD tanpa struktur SRR. Secara berturut-turut hasil simulasi antena tersebut masing-masing antena memiliki dimensi, bandwidth, dan gain sebesar 50 × 50 mm, 3,2%, dan 2,62 dBi untuk antena konvensional; 50 × 50 mm, 5,28%, dan 4,97 dBi untuk antena mikrostrip dengan struktur SRR 5 × 5; serta 30 × 30 mm, 9,4%, dan 2,02 dBi untuk antena berbahan MD tanpa struktur SRR. Simulasi, optimasi, dan pengukuran telah dilakukan sehingga diperoleh antena yang bekerja pada frekuensi 3,5 GHz, dengan fractional bandwidth sebesar 10% (360 MHz), efisiensi radiasi sebesar 58,54%, dan gain maksimum hingga 4,33 dBi. Antena ini berukuran 30 × 30 mm atau 64% lebih kecil dibandingkan dengan antena konvensional. Berdasarkan hasil ini dapat disimpulkan bahwa kombinasi baru antara struktur SRR susun dan bahan sintesis MD yang diusulkan pada penelitian ini dapat membangkitkan karakteristik MD buatan dan alami untuk mereduksi dimensi antena sekaligus meningkatkan performa antena. ......The need for small antennas with high performance has prompted various researches to experiment not only in terms of the structure and shape of the antenna but also in terms of material. Utilization of magneto-dielectric (MD) characteristics both artificial and engineered material in reducing antenna size and improving antenna performance is proposed in this study. The MD characteristics are realized through the SRR array structure and material synthesis. Parametric studies were carried out to determine the dimensions of the SRR and the most optimal SRR configuration to obtain an effect that can improve antenna performance. MD material has been successfully synthesized from a mixture of magnetite powder (Fe3O4) nanoparticles as a magnetic material, an elastic polymer material PDMS (polydimethylsiloxane) as a dielectric material, and BaFe12O19 as additives to aid adhesion with the host dielectric. This MD material has been successfully characterized both in terms of material and electricity. Based on the results of material characterization from XRD, SEM, and VSM measurement, it is known that the mixture is evenly dispersed and has good magnetic properties. Meanwhile, based on the results of electrical characterization through measurements with waveguides and sensors, it is known that the addition of magnetite composition in the sample can increase the relative permittivity and relative permeability of the material. The characterization results were then simulated to design a microstrip antenna by combining the MD substrate and the SRR structure. This microstrip antenna comprises two parts, namely the patch on the MD material, and the SRR array structure on the dielectric material as the antenna ground plane. These two parts are arranged in layers into a single microstrip antenna. The parametric study results show that the antenna designed on sample C (PDMS : Fe3O4 = 1 : 0,6) MD material with 3 × 3 SRR configuration on the dielectric material (εrHost < εrMD) gives the most optimal response. The optimal condition is determined by considering the trade-offs that occur from each variation in the aspect of antenna size reduction and antenna performance. This research has succeeded in finding a method to obtain antennas with smaller dimensions with higher performance than antennas without MD materials and SRR structures. For comparison, the same analysis was carried out at the same frequency for conventional microstrip antennas (without MD material and SRR structure), microstrip antennas with SRR structure without MD material, and MD antennas without SRR structure. The antenna simulation results have dimensions, bandwidth, and gain of 50 × 50 mm, 3.2%, and 2.62 dBi for conventional antennas; 50 × 50 mm, 5.28%, and 4.97 dBi for microstrip antennas with a 5 × 5 SRR structure; and 30 × 30 mm, 9.4%, and 2.02 dBi for MD antennas without SRR structure, respectively. Simulations, optimization, and measurement have been carried out to obtain an antenna that works at a frequency of 3.5 GHz, with a fractional bandwidth of 10% (360 MHz), the radiation efficiency of 58.54%, and a maximum gain of 4,33 dBi. The antenna dimension is 30 × 30 mm or 64% smaller than conventional antennas. Based on these results, it can be concluded that the novel combination of SRR array structure and MD materials proposed in this study can generate artificial and natural MD characteristics to reduce antenna dimensions while increasing antenna performance.

Abstrak :
Antenna can be one of the largest components in a wireless device; therefore antenna miniaturization can reduce the overall size of wireless devices. One method used to reduce the element size of an antenna is by using metamaterial structures. This paper discusses a Left-Handed Metamaterial (LHM) structure stacked on a two-element microstrip antennas array for miniaturization and gain enhancement at a frequency of 2.35 GHz. To observe the impact of the LHM structure on the antenna, first this paper discuss the design of a conventional rectangular shape microstrip antenna without a LHM structure, then a design of the LHM structure which shows both negative permittivity and negative permeability. This LHM structure is then implemented on a conventional single element microstrip antenna and on a two-element microstrip antennas array. Results and discussion of implementation of the LHM structure on the conventional microstrip antenna is provided in this paper. The results show that good agreement between simulated and measured results has been achieved. The simulation results show that the antenna works at a frequency of 2.29?2.42 GHz with a bandwidth of 128 MHz (5.4%) and a gain of 8.2 dBi, while the measurements show that the antenna works at a frequency of 2.26?2.41 GHz with a bandwidth of 146 MHz (6.21%) and a gain of 8.97 dBi. In addition, by comparing the substrate dimension for the two element array antennas, with and without the LHM structure, shows a 39% reduction is achieved.

Abstrak :
Antenna can be one of the largest components in a wireless device; therefore antenna miniaturization can reduce the overall size of wireless devices. One method used to reduce the element size of an antenna is by using meta material structures. This paper discusses a Left-Handed Meta material (LHM) structure stacked on a two-element microstrip antennas array for miniaturization and gain enhancement at a frequency of 2.35 GHz. To observe the impact of the LHM structure on the antenna, first this paper discuss the design of a conventional rectangular shape microstrip antenna without a LHM structure, then a design of the LHM structure which shows both negative permittivity and negative permeability. This LHM structure is then implemented on a conventional single element microstrip antenna and on a two-element microstrip antennas array. Results and discussion of implementation of the LHM structure on the conventional microstrip antenna is provided in this paper. The results show that good agreement between simulated and measured results has been achieved. The simulation results show that the antenna works at a frequency of 2.29–2.42 GHz with a bandwidth of 128 MHz (5.4%) and a gain of 8.2 dBi, while the measurements show that the antenna works at a frequency of 2.26–2.41 GHz with a bandwidth of 146 MHz (6.21%) and a gain of 8.97 dBi. In addition, by comparing the substrate dimension for the two element array antennas, with and without the LHM structure, shows a 39% reduction is achieved.

Abstrak :
Pada penelitian ini, material magneto-dielektrik buatan, yang memiliki permitivitas dan permeabilitas lebih besar dari satu, digunakan untuk meminiaturisasi antena mikrostrip. Teknik miniaturisasi yang digunakan ialah konfigurasi Split-Ring Resonator (SRR) sebagai struktur metamaterial yang dapat bertindak untuk membangkitkan medan magnetik pada susunan substrat dielektrik. Antena dirancang untuk dapat bekerja pada frekuensi UHF yaitu pada rentang 1 GHz-2.2 GHz. Untuk mengetahui karakteristik dan kinerja antena, perancangan disimulasikan menggunakan software CST Microwave Studio. Selain disimulasikan, antena juga difabrikasi pada dua jenis substrat yaitu FR-4 dan RT/Duroid 5880. Dari hasil pengukuran, terdapat peningkatan bandwidth pada bahan FR-4 yang telah diberi struktur SRR mencapai 272.73%, peningkatan gain sebesar 121.36%, dan 191.87% untuk peningkatan efisiensi radiasi antena. Sedangkan pada bahan duroid hanya diperoleh peningkatan bandwidth sebesar 281,91%, penurunan gain sebesar 27.31%, dan 23.56% untuk peningkatan efisiensi. Ditinjau dari jumlah konfigurasi SRR, hasil penelitian menunjukkan bahwa dengan menggunakan konfigurasi SRR 3x3 peningkatan bandwidth hanya sebesar 43,2 MHz pada bahan FR-4 dan 27,4 MHz pada bahan duroid, sedangkan melalui konfigurasi SRR 5x5 dapat diperoleh peningkatan bandwidth hingga 162 MHz pada bahan FR-4 dan 53 MHz pada bahan duroid. Untuk aspek miniaturisasi antena, dari hasil eksperimen diketahui bahwa struktur SRR 3x3 dan SRR 5x5 pada bahan FR-4 berkontribusi sebesar 43.75%, sedangkan pada bahan duroid miniaturisasi yang dicapai hanya 19.28% melalui konfigurasi SRR 3x3 dan 16.67% melalui konfigurasi SRR 5x5. Penggunaan struktur SRR sebagai bahan magneto-dielektrik terbukti mampu meningkatkan bandwidth, gain, dan efisiensi radiasi, sekaligus mampu memberikan kontribusi miniaturisasi ukuran antena. ......In this study, artificial magneto-dielectric material, which has permittivity and permeability greater than unity, was used to miniaturize microstrip antennas. The miniaturization technique used is the Split-Ring Resonator (SRR) configuration as a metamaterial structure that can act to generate magnetic fields in the arrangement of dielectric substrates. Antennas are designed to work on UHF frequencies, which are in the range of 1 GHz-2.2 GHz. To find out the characteristics and performance of the antenna, the design was simulated using CST Microwave Studio software. Besides being simulated, the antenna is also fabricated on two types of substrate namely FR-4 and RT/Duroid 5880. From the measurement results, there is an increase in bandwidth on FR-4 material that has been given the SRR structure reaching 272.73%, an increase in gain of 121.36% and 191.87% for increased antenna radiation efficiency. While for duroid materials only obtained an increase in bandwidth of 281.91%, a decrease in gain of 27.31%, and 23.56% for increased efficiency. Judging from the number of SRR configurations, the results showed that using the SRR 3x3 configuration, the bandwidth increase was only 43.2 MHz on FR-4 and 27.4 MHz in duroid materials, whereas through a 5x5 SRR configuration a bandwidth increase of up to 162 MHz was obtained. FR-4 and 53 MHz in duroid material. For the miniaturization aspect of the antenna, the experimental results revealed that the structure of SRR 3x3 and SRR 5x5 in FR-4 material contributed 43.75%, while in miniaturized duroid material achieved only 19.28% through 3x3 and 16.67% SRR configurations through 5x5 SRR configuration. The use of SRR structure as a magneto-dielectric material is proven to be able to increase bandwidth, gain, and radiation efficiency, while being able to contribute to miniaturization of antenna size.

Abstrak :
High-temperature superconducting (HTS) materials are becoming more and more attractive in the context of designing RF/microwave filters because of their lower losses and excellent performance. This book focuses on the superconducting microwave filter and its application in modern communication. It first presents the basic principles, HTS materials and processing and then introduces several types of multi-band HTS bandpass filter (BPF), discussing their properties and analyzing equivalent circuit models and their performances. This book is a valuable resource for students and researchers who are interested in wireless communication and RF/microwave design.