AbstrakWi-Fi (Wireless Fidelity) merupakan sebuah teknologi yang memanfaatkan peralatan elektronik untuk bertukar data secara nirkabel. Dalam sistem komunikasi wireless bagian terpenting untuk mengoptimalkan kinerjanya adalah antena. Mikrostrip adalah salah satu jenis antena yang praktis mempunyai ukuran dan dimensi yang sederhana dan mudah difabrikasi. Pada penelitian ini dibahas bagaimana desain dan analisa antena mikrostrip dengan bentuk patch sirkular dengan spesifikasi frekuensi kerja 2,400 -2,484 GHz menggunakan substrat FR-4 dengan ketebalan 1,6 mm dan ε = 4,3. Teknik pencatuan yang digunakan adalah dengan teknik microstrip line feed. Perancangan dan simulasi antena mikrostrip dilakukan menggunakan software CST Studio Suite 2016. Antena yag dirancang juga dianalisa menggunakan Characteristic Mode Analysis (CMA). Hasil yang ditampilkan berupa grafik mode-mode arus pada modal significance. Dihasilkan sebanyak dua mode yang berhimpit untuk desain patch A pada frekuensi 3081 MHz dan terjadi perubahan untuk desain patch B, dimana kedua mode berpisah dan bergeser, mode 1 bergeser ke frekuensi 2406 MHz sedangkan mode 2 bergeser ke frekuensi 1889 MHz. Dari antena mikrostrip yang telah difabrikasi dilakukan pengukuran beberapa nilai parameter yaitu, S 11 sebesar -21,13 dB, VSWR 1:1,19, rentang frekuensi 2,37 -2,54 GHz, pola radiasi directional dan gain sebesar 2,15 dBi. AbstractWi-Fi (Wireless Fidelity) is a technology that utilizes electronic equipment to exchange data wirelessly. In wireless communication system the most important part to optimize its performance is the antenna. Microstrip is one type of antenna that has practical size and dimensions are simple and easy to fabricate. This study discussed how to design and analyze microstrip antenna with circular patch form with working frequency specification 2.400 -2.484 GHz using FR-4 substrate with thickness 1.6 mm and ε = 4.3. The technique of unification used is by microstrip line feed technique. The design and simulation of microstrip antenna is done using CST Studio Suite 2016 software. The designed antennas are also analyzed using Characteristic Mode Analysis (CMA). The results are graphs of current modes on modal significance. Generated as many as two modes coincide for the patch A design at a frequency of 3081 MHz and a change occurs for the patch B design, where both modes separate and shift, mode 1 shifts to a frequency of 2406 MHz while mode 2 shifts to a frequency of 1889 MHz. From the microstrip antenna that has been fabricated, the measurement of some parameter values is S 11 -21.13 dB, VSWR 1: 1.19, frequency range 2.37 -2.54 GHz, directional radiation pattern and gain of 2.15 dBi.

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This study aims to assist farmers in monitoring soil nutrients, especially phosphorus. To measure the phosphorus content of paddy soil, the TCS3200 converter, as an intelligent sensor, was applied. The geographical information system (GIS) was also involved in this research to map the phosphorus content. In addition, the Naïve Bayes method was applied to classify lowland soil phosphorus status. The result of this study indicated that the Naïve Bayes algorithm could classify lowland soil phosphorus status with a probability of 0.34 for moderate phosphorus conditions and 0.66 for high phosphorus conditions. The sample testing results showed that the error rate was 3% and the success rate was 97%. Testing with a phosphorus-measuring instrument can be carried out by mapping the soil phosphorus status with the ArcGIS software, whereby seven points of medium-phosphorus-status paddy soil and 13 locations of high-phosphorus-status soil samples were determined. This research thus successfully mapped the soil phosphorus.

This paper presents the design of a planar inverted F antenna with a miniature or tiny shape at the frequency of 2.4 GHz. The antenna uses a spiral design to reduce the dimension of the antenna with conformal shape for a suitable prosthetic arm. Usually, the antenna design uses long experimental steps, namely trial and error. It can be summarized using the DOE (design of experiment) method. The DOE is a method to streamline the experimental steps to get the best design. The DOE method uses a tuning reference at the design parameter variation of 5 % of the nominal value. Four tuning steps can get the best results from S11, bandwidth, and gain. The designed antenna works at the resonant frequency of 2.431 GHz with the value of S11 is -22.634 dB, bandwidth of 37.1 MHz, and gain of -7.596 dBi.

This paper presents the analyzed Monopole Antenna for Ultrawideband with a rectangular patch design using bevel technique at a frequency of 3.1 – 10.6 GHz. The fabricated antennas with dual bevel angles have a very compact width and length of 40 mm x 33 mm respectively and a groundplane width of 13 mm. To get bandwidth improvement on monopole antennas can be applied to the bevel angle on the patch. So, to get the best antenna design, 3 optimizations of antenna size changes were carried out during the simulation, that is optimization of patch length, patch width and bevel angle. Variation of patch length and width is used to change the frequency range and variation of bevel angle to increase bandwidth. From each change, the best result is taken. The experiment obtained the best simulation result of antenna and then fabricate it. From the measurement results on the fabricated antenna, the lowest S11 value is -24.6 dB, gain 2.6 dBi at a frequency of 5 GHz and radiation pattern is omnidirectional. The optimization process using the bevel technique has been proven to be successful in shifting the frequency range by around 600 MHz and increasing the bandwidth by about 4% or 30 MHz.