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This study proposes a new design of wide bandwidth microstrip antennas using dual feed line techniques. To obtain the optimal impedance bandwidth (IBW) and Axial Ratio Bandwidth (ARBW), several iterations were performed by controlling the dimensions and length of the dual feed line. From the simulation results, the proposed antenna obtained IBW of 0.4GHz or 17% and ARBW of 0.38GHz or 15% at an operating frequency of 2.5 GHz. The gain of the proposed antenna was 5.73dB with a directional radiation pattern. The dual feedline technique successfully improved IBW up to 254.16% compared with the single feed technique. This study would be useful especially for bandwidth optimization of microstrip antennas.

The main problem in designing a multiband bandpass filter (BPF) is making each passband response highly independent, where each bandwidth of multiband BPF can be controlled and adjusted separately. To overcome this problem, this paper proposes a highly independent multiband BPF based on a multicoupled line stub-SIR with a folding structure. The proposed multiband BPF is constructed as a multicoupled line to generate a highly independent inter-passband. Moreover, the multiband performance is produced separately and independently by using three sets of resonators: resonator A1/A2 (RA1 and RA2), resonator B1/B2 (RB1 and RB2), and resonator C1/C2 (RC1 and RC2). The three passband frequencies can be independently arranged and designed. To miniaturize the multiband BPF, a folding structure is also proposed. As a result, the multiband BPF has a compact size that is reduced by over 61.29 % compared to previous structures. The even-odd excitation model and the equivalent circuit model are used to analyze the multiband BPF structure. This BPF is designed for GPS applications at 1.57 GHz, WCDMA (3G) at 1.8 GHz, WLAN (WiFi) at 2.4 GHz, LTE (4G) at 2.6 GHz, and 5G communication at 3.5 GHz. To evaluate and validate the proposed structure of the multiband BPF, the circuits are fabricated and tested. The simulated and measured results of the multiband BPF show good agreement. In conclusion, the proposed multiband BPF structure has a highly independent inter passband response and a compact size.

The main problem of intensity modulation (IM) in radio-over-fiber (RoF) communication is dispersion power fading (DPF), which occurs when the signal is transmitted through a dispersive link that causes a sideband cancelation effect. The DPF level of the RoF link is determined by the deviation factor (DF). The optical single-sideband (OSSB) modulation scheme, which is generated by driving one of the dual-drive Mach&ndash, Zehnder modulators (DD-MZMs), is usually used to overcome DPF. The DF value of OSSB modulation at modulation index m = 0.1 increases from 0.008 to 0.930 at m = 1. It can be said that this method is only effective at reducing DF at low m. However, as well-known information of the DD-MZM system, high-efficiency optic&ndash, electric conversions can be obtained at high m values, but DF will increase. Therefore, reducing the DPF value for high m &ge, 0.1 is interesting. It is known that in wireless communication, to reduce the impact of fading, direct signals are amplified and signals with irregular phases are used. Moreover, this paper proposes the DD-MZM with an asymmetric carrier divider as a direct signal and combines it with an irregular radio frequency (RF) phase to reduce the DPF at high m. The carrier that is generated by laser diode (LD) power (PIN) is divided asymmetrically as power modulation (PDD-MZM) and carrier arm (CA) power (PCA). Furthermore, the minimum DF is obtained when the PIN is separated as 75% for PCA and 25% for PDD-MZM with an irregular RF signal of &theta, = 48&deg, and a bias point value of &gamma, = &frac34, As a result, with the same power as OSSB, this proposed structure produces DF at m = 0.1 and m = 1 with values of 0.008 and 0.03, or it can reduce DF of 96.7% at m = 1. The mathematical model and simulation model have very good agreement, which validates the proposed method.

Filter is a device to pass a particular frequency by passing wanted frequency and reduce unwanted frequencies. The frequency that used is depend on the applications used. Based on the frequency regions that are passed, the filter is divideed into several type: Lowpass Filter (LPF), Bandpass Filter (BPF), Highpass Filter (HPF), and Bandstop Filter (BSF). This script was aimed to realized Bandpass Filter (BPF) at frequency 1,8 GHz for long term evolution (LTE). The filter is a hairpin filter, which is one method of designing a distributed element filter with λg/2 length of resonators that is parallel coupled and have resonators topology as ‘U’ shape. Realization of this filters was using microstrip with FR4-Epoxy material as a transmission channel. The information filter performance was measured by using network analyzer. In this BPF designing and realizing, some of the parameters measured are frequency respone, bandwidth, insertion loss, return loss, Voltage Standing Wave Ratio (VSWR). The result of BPF characteristics measurements are: center frequency at 1,8 GHz with 360 MHz bandwidth, insertion loss 8,4 dB, return loss 11,42 dB, VSWR 1,14.

The main problem with the radio-over-fiber (RoF) link is the decrease in the recovered radio frequency (RF) power due to the chromatic dispersion of the fiber known as dispersion power fading. One of the methods for dealing with dispersion power fading is to use the optical single sideband (OSSB) modulation scheme. The OSSB modulation scheme can be generated by biasing the dual-drive Mach&ndash, Zehnder modulator (DD-MZM) to the quadrature bias point (QBP) and shifting the RF drive signal phase (&theta, ) by 90&deg, which is called the regular &theta, However, the OSSB modulation scheme only overcomes dispersion power fading well at the modulation index (m) &lt, 0.2. This paper proposes an irregular &theta, method to overcome dispersion power fading at all m. There are two irregular &theta, for every m used. The irregular &theta, managed to handle dispersion power fading better than OSSB modulation scheme did at every m. Specifically, the irregular &theta, could handle the dispersion power fading well at m &le, 1. In sum, the irregular &theta, could overcome the dispersion power fading at any RF frequency and optical wavelength without having to re-adjust the transmitter.

Radar merupakan sebuah perangkat yang menggunakan gelombang elektromagnetik yang berguna untuk mendeteksi, mengukur jarak, kecepatan dan memetakan objek bergerak maupun diam. Radar maritim adalah stasiun radar bergerak yang dipakai diatas kapal laut sehingga dapat mencakup daerah yang luas di wilayah perairan Indonesia. Radar maritim digunakan untuk mengawasi perairan laut Indonesia. Salah satu subsistem radar maritim adalah antena, Antena berfungsi memancarkan gelombang elektromagnetik ke udara bebas. Untuk menghasilkan coverage area yang luas diperlukan antena dengan gain yang tinggi. Berdasarkan kondisi tersebut maka pada penelitian ini akan diusulkan penggunaan metode patch circular dengan metode array 1x8. Metode patch circular berguna untuk menghasilkan antena yang bekerja pada frekuensi 3,2 GHz. Metode array 1x8 berguna untuk meningkatkan gain antena tanpa merubah fasa dari sinyal. Hasil pengujian menujukkan bahwa semakin banyak elemen banyak, gain semakin tinggi dan memenuhi kriteria yang diharapkan

Desain Power Amplifier Frekuensi 135 Mhz Untuk Perangkat Transmiter Vhf Dittel Portable. Power amplifier (PA) merupakan komponen akhir pada bagian pemancar VHF Dittel Portable yang berfungsi untuk menguatkan sinyal yang dikirimkan dari sumber. Pada perancangan ini power amplifier dibuat untuk bekerja pada frekuensi 135 Mhz. PA yang diusulkan menggunakan Transistor Tipe Mosfet MRF 136 dengan power supply V= 30 V, VDD= 28 Vdan ID= 1.2 A agar memperoleh gain dan output power yang besar. Untuk menigkatkan coverage area komunikasi pada saat flight check calibration. Perancangan PA menggunakan L-Network dan phi- Matching digunakan sebagai rangkaian matching input dan matching output. Tipe bias transistor yang digunakan yaitu power-divider karena memiliki tingkat sensitifitas perubahan  paling rendah terhadap perubahan suhu. Hasil dari simulasi dan perhitungan yang telah dilakukan mendaptkan nilai-nilai dari spesifikasi power amplifier diperoleh nilai kestabilan > 1, gain (S21) = 20 dB, output return loss (S11) = -33.89 dB. Dengan power output sesuai dengan yang diharapkan sebesar 10 watt atau 40 dBm dan bekerja tepat pada frekuensi kerjanya 135 Mhz.

Perkembangan telekomunikasi semakin pesat, mendorong dilakukannya berbagai penelitian dibidang komunikasi wireless (nirkabel). Salah satu subsitem dari perangkat komunikasi yaitu mixer atau lebih dikenal dengan modulator. Pada penelitian ini diusulkan perancangan downconverter resistive mixer pada frekuensi 900 MHz. Frekuensi 900 MHz merupakan frekuensi kerja Global System for Mobile communications (GSM). Penggunaan downconverter resistive mixer memiliki kelebihan diantaranya rangkaiannya sederhana dengan nilai gain yang besar. Perangkat lunak Advance Design Sistem (ADS) dipergunakan untuk perancangan mixer ini. Hasil perancangan menunjukan nilai Gain lebih besar dari 20 dB dengan kestabilan sebesar 1,4. Selain itu mixer ini memiliki nilai linieritas yang tinggi dengan kompresi 1-dB saat power sebesar 20 dBm.

Some problems that appeared in designing wideband bandpass filter (BPF) using microstrip are large size, difficult structure, the filter parameters are large and too complicated, and have narrow passband. In order to overcome some of these problems, a compact quad-wide fractional bandwidth (QW-BPF) using stub step impedance resonator with meandering structure is proposed, designed and analyzed in this paper. The proposed resonator is constructed by dual-stub step impedance resonator (DS-SIR) to produce several transmission zeros with four wide passbands and good transmission coefficients. In order to reduce the filter size, a meandering structure also was proposed. This QW-BPF achieves good transmission coefficients/ wide-fractional bandwidth of 0.59/58.36, 1.16/34.55, 1.67/16.44, and 2.43 dB/15.42% at 0.85, 1.65, 2.54, and 3.43 GHz, respectively. The experimental verification was tested and implemented practically. The simulation and measurement result has a very good agreement. The proposed QW-BPF has wide-fractional bandwidth, good transmission coefficients, ease of fabrication, and compact size. The simulated and measured reports are provided and they had good agreement.

A quad-band low noise amplifier (QB-LNA) based on multisection impedance transformer designed and evaluated in this research. As a novelty, a multisection impedance transformer was used to produce QB-LNA. A multisection impedance transformer is used as input and output impedance matching because it has higher stability, large Q factor, and low noise than lumpedcomponent.The QB-LNA was designed on FR4 microstrip substrate with er= 4.4, thickness h=0.8 mm, and tan d= 0.026. The proposed QB-LNA was designed and analyzed by Advanced Design System (ADS).The simulation has shown that QB-LNA achieves gain (S21) of 22.91 dB, 16.5 dB, 11.18 dB, and 7.25 dB at 0.92 GHz, 1.84 GHz, 2.61 GHz, and 3.54 GHz, respectively.The QB-LNA obtainreturn loss (S11) of -21.28 dB, -31.87 dB, -28.08 dB, and -30.85 dB at 0.92 GHz, 1.84 GHz, 2.61 GHz, and 3.54 GHz, respectively. It also achieves a noise figure (nf) of 2.35 dB, 2.13 dB, 2.56 dB, and 3.55 dB at 0.92 GHz, 1.84 GHz, 2.61 GHz, and 3.54 GHz, respectively. This research also has shown that the figure of merit (FoM) of the proposed QB-LNA is higher than that of another multiband LNA.

Technology of 4G is a cellular technology improved from 3G and 2G which provide network with the bandwidth of 75MHz and operated frequency of 1800 MHz. In a process of receiving and sending information signal, 4G system need antenna as the device functioning to send electromagnetic to the air. When information signal is transmitted, there was possibility that the signal weaken which caused by several factors such as air, building wall thickness and weather. Rectangular circular patch array 1x8 microstrip antenna is an antenna functioning as 4G signal strengthens at the frequency of 1800MHz. Antenna was design by using software of CST Studio Suite. From the result of rectangular circular patch array 1x8 microstrip antenna measurement at the frequency of 1800 MHz, it was obtained that the gained was 7.32 dB, VSWR was 1.208, and return loss was -20.3 dB. Performance test of antenna was conducted for 4 Indonesia’s cellular providers namely Telkomsel, Indosat Ooredoo, XL, and 3 in various places. The test result in PNJ telecommunication laboratory showed that the best average value of RSRP from provider of Indosat Ooredoo was-72.9 dBm, the best average value of RSPP from provider of 3 was -70.7 dBm located in Bambon raya, and the best average value of RSPP from provider of XL was -65.2 dBm located in Cibubur.

In this paper, circular-shaped microstrip antenna was simulated, fabricated, and measured accordingly. As the novelty, to enhance bandwidth and reduce antenna size, beleved half-cut microstrip structure is proposed. Further, this proposed antenna structure will be applied to multiple input multiple output (MIMO) antenna 2´2. Therefore, this research was investigated conventional circular shape antenna (CCSA), circular shaped beleved antenna (CSBA), and MIMO circular shaped beleved antenna (MIMO-CBSA) as Model 1, Model 2, and Model 3, respectively. An FR4 substrate with er= 4.4, thickness h=1.6 mm, and tan d=0.0265 was used. The simulation has been conducted using Advanced Design System (ADS). The antenna CCSA/CSBA/ MIMO-CBSA achieve 1.831GHz/2.265 GHz/2.256 GHz, -15.13dB/-17.37dB/-17.25 dB, 1.42/1.31/1.33, and 1.474/2.332/2.322 for center frequency, reflection coefficient, VSWR, and bandwidth, respectively. This antenna has a size 63x90 mm and 51.5x90 mm for CCSA (Model 1) and CSBA (Model 2), respectively. After the structure of MIMO 2´2 was applied, the size of antenna MIMO-CBSA (Model 3) became 180 mm x 180 mm with a mutual coupling (S21)=-26.18 dB and mutual coupling (S31)=-26.41 dB. The result showed that proposed antenna CSBA (Model 2) has wider-bandwidth of 58,2% and smaller-size of 18.2%. Furthermore, after CSBA (Model 2) structure was applied to MIMO 2´2 (Model 3) and the MIMO antenna obtain good mutual coupling (

This research was proposed a circular patch MIMO antenna by using a ring and circular parasitic radiator structure. As a novelty, in order to enhance bandwidth and gain of circular patch MIMO antenna, a conventional circular patch MIMO antenna will be added a ring and a circular parasitic. Therefore, this research was investigated a conventional MIMO antenna (C-MA), ring parasitic MIMO antenna (RP-MA), and circular parasitic MIMO antenna (CP-MA) as Model 1, Model 2, and Model 3, respectively. This MIMO antenna was designed on FR4 microstrip substrate with r= 4.4, thickness h=1.6 mm, and tan = 0.0265. This MIMO antenna has center frequency 2.35 GHz which is a frequency band for LTE application in Indonesia. An Advance Design System (ADS) software was used to determine the antenna parameters. The MIMO antenna C-MA / RP-MA/ CP-MA achieves 2.36GHz/ 2.38GHz/ 2.38 GHz, 70 MHz/ 100 MHz/ 120 MHz, 1.625 dBi/ 4.066 dBi/ 4.117 dBi, 6.414 dBi/ 7.26 dBi/ 7.153 dBi, 33.9 %/ 47.8 %/ 49.70 %, -12.35 dB/ -22.21 dB/ -23.66 dB, and -30.924 dB/ -28.46 dB/ -27.59 dB for center frequency, bandwidth, gain, directivity, efficiency, reflection coefficient, and mutual coupling, respectively. Compared to C-MA (Model1) performances, The result showed that proposed antenna has wider-bandwidth/ higher-gain with 42.8%/ 150.2 %, and 71.4%/ 163.3% for RP-MA (Model 2) and CP-MA (Model 3), respectively. The proposed antenna has size of 50 mm x 130 mm x 23.2 mm. Measured results are in a good agreement with the simulated results.