CIRCULARLY POLARIZED MICROSTRIP ARRAY ANTENNA FOR GROUND SEGMENT IN QUASI-ZENITH SATELLITE SYSTEM

In satellite communication system, antenna plays an important role. Therefore, the antenna must meet some requirements, such as high gain, circular polarization, and good directivity. In this paper, a four element linear array triangular patch microstrip antenna with cross slot is designed to be used for Quasi-Zenith satellite system. A simulation study as well as experimental study was carried out. The simulation showed that the 3 dB axial ratio bandwidth of 87 MHz (2.569-2.656 GHz) is achieved while the measured results showed 96 MHz (2.556-2.652 GHz). The linear array of 4 element antenna has a gain of 13.73 dB and maximum radiation pattern at 40° and -40°. Simulation and experiment results show that this antenna has met the characteristic requirements of Quasi-Zenith satellite. Keywords: circular polarization, cross slot, microstrip antena array, Quasi-Zenith satellit

Reconfiguration of Polarized Antennas for WLAN Applications

Wireless technology based on the IEEE 802.11 standard and in accordance with the KEMINFO 2019 regulations requires antennas that can adapt to changing environments. Microstrip antennas are a good solution to meet the current technological advancements because they have several advantages, such as a simple design, lightweight, easy manufacturing, and low cost. When designing a microstrip antenna, bandwidth parameters must be observed. The bandwidth of a microstrip antenna is narrow. In order to work properly, some simple techniques can be used to increase antenna bandwidth. This research proposes a reconfigurable microstrip antenna polarization using a U-slot at a frequency of (2.4– 2.485) GHz for WLAN applications. The proposed antenna reconfiguration utilizes two (2) switching mechanisms that can be turned on and off individually or simultaneously. The results of the simulation showed that Ant. 1 and Ant. 2 have a linear polarization (LP), Ant. 1 has a bandwidth of 85 MHz (2.399 – 2.484) GHz, and Ant.2 has a bandwidth of 87 MHz (2.398– 2.485) GHz, both with S-parameter values ≤-9.54 dB. Then, Ant. 3 has a right circular polarization with a bandwidth value of 124 MHz (2.397 – 2.484) GHz, and Ant. 4 has a left circular polarization with a bandwidth value of 87 MHz (2.398 – 2.485) GHz at the Axial Ratio (AR) limit of ≤ 3 dB

PERANCANGAN PEMBANGKITAN FREKUENSI GANDA ANTENA MIKROSTRIP SEGITIGA SAMA SISI MENGGUNAKAN TEKNIK SAMBATAN ELEKTROMAGNETIK

Design of Generating Dual Frequency Operation for Triangular Microstrip Antenna Using ElectromagneticCoupling. A new design is proposed in this paper by applying a pair of slits using a microstrip feed line. Therefore themicrostrip line feeding system is electromagnetically coupled to the patch. The antenna works at two differentfrequencies in the range from 2 GHz to 4 GHz (S band frequency). The results of the simulation shows that the dualfrequency operation can be created when the slit width is 1 mm and the height of the slits ranges from 10 mm to 14 mmwith inter slit distance of 3 mm, 5 mm and 7 mm as well.Keywords: dual frequency, triangular microstrip antenna, microstrip lin

The improvement of fiber-detection method to enhance the output of amplify-received relaying on FSO communications

The performance of free-space optical (FSO) communications that using an optical amplifier (OA) in the scheme of an amplify-received (AR)-relaying has a major drawback in the detection of input signal quality under the effects of turbulence. As an OA is based on a fiber-detection (FD) method to receive and delivers a signal at the amplification process stage, there is an opportunity to implement an optical filter to improve the quality of the input signal. In this paper, as the continuation of previous work on improvement of direct-detection, the optical filter is applied on the AR-relaying of optical signal detection, implementing an OA in the receiver. The novelty proposed in this work is the improvement of FD method where the OF is designed as the integration of cone reflector, pinhole and multi-mode fiber with an OA. The optical filter produces an optical signal, the input of the OA, which minimizes the effects of turbulence, background noise and the fluctuation of the signal spectral. Thus, OA in AR-relaying produces signal output with high power and rise up below threshold level. Additionally, an OF with a lower pinhole diameter produces the best quality of the signal spectral to be delivered into an EDFA. Through this implementation, the performance of optical relaying network on FSO can be significantly improved

PENGEMBANGAN ANTENA MIKROSTRIP SUSUN DUA ELEMEN DENGAN PENERAPAN DEFECTED GROUND STRUCTURE BERBENTUK TRAPESIUM

Two Element Microstrip Antenna Array with Defected Ground Structure. This paper presents a two elementmicrostrip antenna array using trapezium shape defected ground structure (DGS). The DGS is inserted in the groundplane between two elements of antenna array. Insertion of the DGS is intended to suppress the mutual coupling effectproduced by antenna array. Simulation and measurement results were taken and compared between antenna array withand without DGS. Measurement results show that the antenna with DGS compared to antenna without DGS cansuppress mutual coupling effect to 7.9 dB, improve the return loss to 33.29% from -30.188 dB to -40.24 dB and axialratio bandwidth enhancement to 10 MHz. This bandwidth enhancement is achieved from frequency 2.63 GHz – 2.67GHz for antenna without DGS and from frequency 2.63 GHz – 2.68 GHz for antenna with DGS. In addition, the DGSantenna also improved the antenna gain to 0.6 dB. The results show that the implementation of the trapezium DGS canimprove the radiation properties of the antenna without DGS.Keywords: defected ground structure, microstrip antenna array, trapezium, mutual couplin

Left-Handed Metamaterial (LHM) Structure Stacked on a Two-Element Microstrip Antenna Array

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

A Simple Folded Dipole Antenna for Medical Implant Communications at 900 MHz Band

Abstract -Nowadays, implanted medical devices that are using inductive coupling for communication, cannot be used for transmitting medical data in several meters range. This triggers us to study about implantable device systems in order for communications is enabled to be longer range by transmitting wirelessly electromagnetic signal. In this system, the external devices such as home monitoring device or portable equipment will provide the patient more mobility, and the patient or the health care provider could benefit from timely and ease of access to important patient medical information via a networked connection. Due to such advantages, small antennas for implantable devices are very important components in monitoring systems to provide wirelessly communication between a patient and an access point. This paper proposes a simple structure of a folded dipole antenna for an implantable device aimed at wireless patient monitoring applications. The implantable device is assumed to be used with a syringe injection, so the device can be simply embedded into the human body. The antenna is operated in UHF band 924 MHz, which is band of Indonesian frequency allocation for RFID applications. The antenna is small enough in this band with good performances such as S parameter, impedance bandwidth, radiation pattern and gain. The antenna has enough gain for more than 10m range communication with 250 MHz bandwidth (VSWR 1.5)

The improvement of fiber-detection method to enhance the output of amplify-received relaying on FSO communications

The performance of free-space optical (FSO) communications that using an optical amplifier (OA) in the scheme of an amplify-received (AR)-relaying has a major drawback in the detection of input signal quality under the effects of turbulence. As an OA is based on a fiber-detection (FD) method to receive and delivers a signal at the amplification process stage, there is an opportunity to implement an optical spatial filter (OSF) to improve the quality of an input signal. In this paper, as the continuation of previous work on the direct-detection, the OSF is applied on the AR-relaying. The novelty proposed in this work is the improvement of FD method where the OSF is designed as the integration of cone reflector, pinhole and multi-mode fiber with an OA. The OSF produces an optical signal, the input of the OA, which minimizes the effects of turbulence, background noise and signal fluctuation. Thus, OA in AR-relaying produces signal output with high power and rise up below threshold level. Additionally, an OSF with a lower pinhole diameter produces the best quality of the signal spectral to be delivered into an EDFA. Through this implementation, the performance of optical relaying on FSO can be significantly improved