Articles
<![CDATA[Analisa Karakteristik Kanal HF Lintasan Jamak ]]>
<![CDATA[Rizki Nugraha Hidayat]]>;
<![CDATA[Umaisaroh Umaisaroh]]>;
<![CDATA[Said Attamimi]]>
<![CDATA[ Jurnal Teknologi Elektro Vol 11, No 3 (2020) ]]>
Publisher : <![CDATA[Electrical Engineering, Universitas Mercu Buana ]]>
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DOI: 10.22441/jte.2020.v11i3.002
<![CDATA[Indonesia merupakan negara kepulauan terbesar di dunia. Oleh karena itu, diperlukan konsep dan perencanaan sistem komunikasi jarak jauh yang murah dan handal agar bisa terhubungnya komunikasi di wilayah kepulauan yang relatif sulit dijangkau oleh sistem kabel yang sudah terhubung saat ini. Sistem komunikasi high frequency (HF) yang beroperasi pada frekuensi 3-30 MHz. Sistem ini memanfaatkan lapisan ionosfer sebagai media transmisi gelombang radionya. Lapisan ionosfer sangat dipengaruhi oleh aktivitas matahari dan perubahan waktu sepanjang hari. Hal ini berakibat timbulnya gangguan-gangguan ionosfer yang menyebabkan kinerja sistem komunikasi HF terganggu juga kondisi dimana terdapat interferensi ketika sinyal lebih dari satu jalur pada saat ditransmisikan hal ini dinamakan multipath atau lintasan jamak. Karakteristik kanal HF menjadi hal yang sangat penting. Dengan mengetahui karakteristik kanal HF yang tepat kita dapat mencapai kinerja sistem komunikasi yang lebih baik. Perubahan kondisi lapisan ionosfer berpotensi mempengaruhi kinerja sistem komunikasi HF yang disebabkan oleh nilai delay spread. Pada penelitian ini dilakukan analisa parameter karakteristik kanal HF mengenai power delay profile dan delay spread yang dilakukan dengan uji simulasi. Berdasarkan hasil percobaan dalam kurun waktu 2 bulan. Dilakukan sebanyak 8 kali percobaan dalam 4 waktu yang berbeda. Menghasilkan nilai delay spread maksimal terjadi pada pagi hari yaitu bernilai 124,1 ms berbeda dengan sore hari yang memiliki nilai 41 ms.]]>
<![CDATA[Design of A Dual-Band Microstrip Antenna for 5G Communication ]]>
<![CDATA[Ahmad Firdausi]]>;
<![CDATA[Lusi Damayanti]]>;
<![CDATA[Galang Persada Nur Hakim]]>;
<![CDATA[Umaisaroh Umaisaroh]]>;
<![CDATA[Mudrik Alaydrus]]>
<![CDATA[ Journal of Integrated and Advanced Engineering (JIAE) Vol 1, No 1 (2021) ]]>
Publisher : <![CDATA[Asosiasi Staf Akademik Perguruan Tinggi Seluruh Indonesia (ASASI) ]]>
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DOI: 10.51662/jiae.v1i1.15
<![CDATA[The necessity for mobile communication devices is increased rapidly. Users expect to get very fast information access and data access without delay. The fifth-generation (5G) development in wireless mobile telecommunication technology promises capacity enhancement, ease connectivity, high efficiency, and high data rate transmission. The appropriate device should support this improvement of the technology. The antenna is one of the main devices to support the high data rate transmission. This paper proposed designing a dual-band rectangular patch antenna in 29 GHz and 38 GHz that supports 5G technology. This microstrip antenna is composed of 4 patch array elements to obtain higher gain. The material used for this microstrip antenna is RT Duroid 5880 with a dielectric constant of 2.2 and a thickness of 1.575 mm. Both measurement and simulation are confirmed that the 2×2 array microstrip antenna in 29 GHz and 38 GHz frequency have a return loss value of -12.5 dB and -16 dB, respectively. The bandwidth for both frequencies has a value of 4.5 GHz and 3.75 GHz.]]>
<![CDATA[Optimized multibeam synthesis of time-modulated microstrip arrays ]]>
<![CDATA[Mudrik Alaydrus]]>;
<![CDATA[Said Attamimi]]>;
<![CDATA[Umaisaroh Umaisaroh]]>
<![CDATA[ Indonesian Journal of Electrical Engineering and Computer Science Vol 28, No 3: December 2022 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijeecs.v28.i3.pp1563-1572
<![CDATA[The capability to form the main beam of antennas improves the energy efficiency of wireless systems and enhances radar systems' effectiveness in detecting and tracking objects. The time-modulated array can generate multibeam with arbitrary directions in different spectral parts. This work synthesizes several linear arrays to achieve particular main beams and additional restrictions. We modify the pulse durations and the switch-on instants of the switches in each antenna element in an optimization procedure. The parameters are varied through the simulated annealing by minimizing certain cost functions. We designed three linear arrays: model 1 consists of six elements and has two beams. Model 2 is the improved version of model 1 by rejecting the sidelobes of other spectral contributions at the main beam under consideration. Model 3 consists of sixteen elements and has three different beams. The analytical results were verified by modeling the arrays in the form of microstrip arrays in a numerical simulation with HFSS. We obtained very accurate verification. Distinctive devitations at the region ϑ<-60o and ϑ>60o originate from the radiation characteristics of microstrip antennas, which focus the energy upwards to the region around ϑ=0o.]]>
