This paper presents the design, simulation, realization and analysis of flexible microstrip patch antenna for S-band applications. The proposed design also adopts the conformal structure by utilizing flexible substrate. Conformal or flexible structure allows the antenna to fit with any specified shape as desired. The antenna patch dimensions is 43 mm × 25 mm without SMA connector. The patch is etched on the flexible dielectric substrate, pyralux FR 9111, with a relative dielectric constant of εr = 3 and the thickness of substrate, h = 0.025 mm. The antenna is designed to resonate at 3.2 GHz. The return loss (RL) of the simulation is -35.80 dB at the center frequency of 3.2 GHz. The fabricated antenna prototype was measured at different bending angles scenarios including 0º, 30º, 60º, and 90º. The measurement of antenna prototype shows that the center frequency is shifted to the higher frequency of 3.29 GHz, compared to the simulation result. Among these scenarios, measurement at bending angle of 90º gives the best performance with RL = - 31.38 dB at 3.29 GHz, the bandwidth is 80 MHz, and the impedance ZA = 48.36 + j2.04 Ω. Despite a slight differences from simulation results, the designed antenna still performs well as expected.
Indonesia as an agricultural country has agricultural lands are quite spacious and most of the people working in this sector. However, agricultural production has not yet fulfilled domestic demand. One effort to increase agricultural production is to apply precision farming method where conducted monitoring and analysis of soil conditions prior to land management activities by using sensor technology. This paper described the development of sensor systems for measuring ion phosphate concentration as the main nutrient. The sensor employs an electrochemical amperometric measurement technique, based conductive polymer as an ion-sensitive membrane through electro-polymerization technique and electrode fabrication using thick film technology. Three configuration electrodes has been used for the sensor and working and auxiliary electrode was made by carbon while the reference electrode fabricated use silver|silver chloride. The ion phosphate sensor was characterized using a standard phosphate solution 10−6 - 10−2 M and produced current about 4 to 41 μA with 98 % linearity, and 150 seconds average of response time. In addition, signal conditioning and data acquisition as electronic circuit system which has support the sensor have been designed and fabricated.
A stepped-impedance bandstop filter with extended upper passbands and improved passband reflections AIP Advances 6, 095106 (2016) Abstract. A microwave planar filter using multi-poled Hairpin resonators in a Roger substrate is proposed for narrow-band operation in S-band applications. The proposed filter is composed of several pole resonators with Hairpin structures and designed with planar structures on a Roger substrate. 100 MHz bandwidth in 3 GHz operational frequency is designed for the proposed filter. Calculation methods using simulation software and results of the characteristics are discussed and reported. The proposed device is analyzed using Advanced Design System (ADS) software where the substrate with dielectric constant of 3.48 and thickness of 1.524 mm is used. The designed device has a simple and compact structure, easy in design and fabrication, and compatible with integrated microwave circuit.
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