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In this study, a compact multiband antenna employing a wideband dual zeroth-order resonator (ZOR) is proposed for mobile handset applications. The theory of wideband zeroth-order mode and multimode is used to design the proposed antenna covering LTE850/900 (824?960 MHz), LTE1700/1800/1900/2100 (1710?2170 MHz), LTE2300 (2300?2400 MHz), LTE2600 (2500?2690 MHz), and Wi-Fi (2400?2500 MHz) bands. In order to achieve wideband operations, the proposed antenna consists of a low-band ZOR and a high-band ZOR that can generate and merge resonance frequencies of zeroth-order, negative-order, and positive-order modes. The performance of the antenna is verified by both full-wave simulations and experiments. The overall size of the antenna is 40mm×6mm×3mm. The antenna provides omnidirectional radiation patterns and measured radiation efficiencies exceeding 43% and 47% for low and high bands, respectively.

Satellite communication has reached a turning point in transmitting data quickly and receiving signals clearly in faraway places. This paper presents a metamaterial-based antenna for distant and military applications that overcomes restrictions and performs unmatched. This project explores metamaterials to create a unique antenna. Expect to be astounded by its power to bend electromagnetic waves, miniaturize, and change our relationship with the universe. The feeding mechanism of this antenna is a modified co-planar waveguide. At 5.6 GHz, the proposed antenna unit cell measures 0.076 , making it small thanks to its MTM characteristic. CP radiation is made when two orthogonally polarized modes are stimulated at the same time and two composite right- and left-handed transmission line unit cells are placed orthogonally. Reduced size, increased bandwidth, and improved Learn how this discovery opens new doors for high-resolution photography, broadband internet, and space exploration. One nanostructure that makes up a metamaterial is the Split Ring Resonator (SRR). SRR dimensions must be smaller than the resonance wavelength, making them crucial for near-infrared and optical responses. This effort examined nanoscale SRR characteristics in the infrared and visible ranges. SRRs composed of aluminum (Al) and gold (Au) were produced on silicon and silica substrates using electron beam lithography (EBL). The proposed structure consists of a microstrip-line-supplied SRR, a parasitic patch that is perpendicular to the ground plane, and two via holes connected by two split rings that feed the patch indirectly. Choosing the right material parameter for all such antennas depends on the planned structure. Fabrication and testing of the antenna matched simulations. Dimensions: 23.7 mm × 16.2 mm × 1.6 mm; substrate dielectric constant: 4.4. Experimental data are detailed and compared to analytical calculations. Simulation results show that metamaterials have negative permittivity and permeability in a certain frequency range, which can be predicted by an analytical method. Simulations indicated eight BRS, WiMAX, radar, and mobile phone resonance frequencies. Radiation is dipole-like in the omnidirectional in the H-plane and E-plane. 10 dB return loss and 3 dB axial ratio bandwidths are 38.6.7% and 8.1%, respectively.

본 논문에서는 과거벡터를 이용한 개선된 성능의 멀티밴드 구조의 부밴드 적응 필터 알고리즘을 제안한다. 기존 부 밴드 적응 필터 알고리즘은 적응 필터의 현재의 계수 벡터만을 가지고 다음 계수 벡터를 업데이트하기 때문에 주변 환경의 잡음이 높을 경우, 필터 계수의 심한 변동으로부터 취약하다는 단점이 있다. 이러한 문제를 해결하기 위해, 적응 필터의 과거계수 벡터와 평균을 취하는 방법을 활용하여 현재의 계수 벡터를 업데이트하는 방법을 제안한다. 제안하는 방법을 통해 처음으로 인접투사 방법을 활용한 부밴드 적응 필터링 알고리즘에 과거계수 벡터를 사용하였고, 부밴드 적응 필터의 계수벡터 개수를 적응적으로 설정하였다. 컴퓨터 시뮬레이션 결과, 제안된 알고리즘은 주변 환경의 잡음에 강인한 성능을 보인다. 또한, 출력신호의 오차를 통해 과거벡터 개수를 상황에 따라 적절히 조절함으로써 수렵 속도를 향상시켰다.

In this paper, an improved multiband-structured subband adaptive filter using past weight vectors is proposed. In case of high background noise, heavy fluctuation can occur in the estimated weight vector since the conventional subband adaptive filtering algorithm updates the next weight vector by using the present weight vector. To solve the problem, we propose a new method of updating the present weight vector in the multiband- structured subband adaptive filter by averaging present and past weight vectors. Through the proposed method, we use past weight vectors for subband adaptive filtering algorithm using an affine projection method at first, whereby the number of past weight vectors is adaptively determined. Computer simulation results demonstrate the robust performance of the proposed algorithm even in case of high background noise. Also, it is shown that the convergence speed can be improved by adaptively controlling the number of past weight vectors depending on the output error information.

워터 렌더링은 오래전부터 연구가 이루어져 왔고, 오늘날 중요한 연구 분야가 되었다. 특히 게임 분야에서 물 렌더 링은 현실 세계와 같은 환경을 나타내는데 중요한 부분이다. 본 논문에서는 바다의 물결을 여러 정현파의 중첩으로 표현할 수 있다는 원리를 기반으로 스펙트럼 모델을 사용한다. 바다의 전체적인 파도의 모습을 나타내는 저해상도의 대역과 작은 파도를 나타내기 위한 고해상도의 대역을 주파수 영역에서 합성함으로서 물 표면을 생성한다. 이전의 연 구에 비해 렌더링 속도는 떨어지지 않으면서 보다 밴드 합성으로 인해 넓은 대역의 주파수 밴드를 갖게 됨으로서 보 다 더 세밀한 바다 표면을 나타낼 수 있는 방법은 연구하였다. 이로서 넓은 대역폭으로 인해 바다의 큰 물결 뿐만 아니라 작은 물결까지도 보다 더 섬세하게 나타낼 수 있다.

Water rendering has been a major research topic for a long time and it become more and more important research field nowdays. In case of game, especially water rendering is an important part for representing the environment of real world. In this paper, water rendering by using the multiband synthesis based on the spectrum model of superposition of sinusoid for ocean wave is proposed. Water surface is generated by synthesizing the spectrum of broad band wave and of high frequency band corresponding to a small wave. Compared with previous studies, the proposed method represents the detailed surface of ocean wave because of the use of wider bands of frequency while not losing the speed. Therefore, the various wave as well as the common ocean wave can be described with adding some frequency bands.

This paper presents a frequency reconfigurable inverted circular patch antenna with U-slot. The incorporation of U-slot in the circular patch provides a wide impedance bandwidth than conventional patch antenna. By introducing shorts at appropriate position on U-slot and on feed, antenna can be made resonant at two frequency bands (1.80GHz-1.98GHz) and (2.10GHz-2.68GHz) in two modes. The proposed antenna not only avoid the interference problem faced in fixed dual band antenna but at the same time provides a good gain of nearly 8 dB in both mode of operation. The prototype of optimized antenna is fabricated and experimental results are in close agreement with the simulated one. This antenna can be used for different wireless application like Personal Communication System (PCS) and Bluetooth/WLAN.

This paper presents the conventional and multiband Orthogonal Frequency Division Multiplexing (OFDM) simulation software named Signal Modulation Simulator (SiMiSIM). A simulation system was built with a Graphical User Interface (GUI) to provide a more user friendly interface than contemporary or command line interfaces. Three basic frequency modulation techniques were made available in SiMiSIM: Binary Phase Shift Keying (BPSK), Quadrature Phase-Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM). Each of the signals had to face Forward Error Correction (FEC) encoder to enhance the signal robustness at the receiver end. The simulation was able to simulate Bit Error Rate (BER) and Power Spectral Density (PSD) for research purposes as well as educational purposes.

This paper presents an architecture of Multiband Impulse Radio UWB (MB-IR-UWB) system based on Prolate Spheroidal Wave Function (PSWF) by binary time hopping pulse position modulation (TH-PPM) over multipath fading channel. In order to combat multipath fading, Rake receiver using maximal ratio combining (MRC) is applied to this system, which can successfully capture the unique multipath-rich property and multipath-clustering phenomenon of UWB channels. Through simulation, a comparison of system performance between different types of Rake receiver is analyzed. What’s more, considered multipath delay spread, a data rate estimation of the communicating system is given. Finally we get the conclusion that increasing data rate is best-achieved by increasing the number of subband instead of decreasing the symbol repetition period.

In this paper we proposed a multi band antenna in which fed is provided by SMA Coaxial Probe. This antenna is contain circular patch and Microstrip line. Using Microstrip line and providing different feed the antenna provide different frequency band. These are 1.2-1.4GHz, 1.6-1.7GHz and 2.1 to 10.7GHz. In this paper we design and simulated antenna use for different application. Here we use FR4 substrate for the design of antenna. The simulation of our proposed design is done with the help of full wave electromagnetic software which is based on FIT.

Microstrip patch antennas have made great advancements in wireless communication field in recent years. They have many advantages like light weight, low cost, smaller size, easy fabrication, high data rates, and capability to operate at multiband and wideband. They can be directly printed on a PCB and are gaining popularity in mobile phones. As the demand of operational bands increases, the design procedure of microstrip antenna is becoming very difficult. The microstrip antenna must be compact in size to employ them in miniaturized portable devices. Microstrip antenna comprise of rectangle, square, circle, triangle, donut, and dipole shaped patches. This paper presents design and development of a microstrip patch antenna for multiband wireless applications. The proposed geometry contains a substrate having rectangular radiating patch with symmetrical E-shaped slots on one side and a ground plane on other side. The designed miniaturized antenna has dimensions of 25 x 25 x 1.58 mm. The performance parameters-operating frequency, return loss (S11), and voltage standing wave ratio (VSWR) are computed for the designed geometry. The fabricated antenna exhibits five frequency bands from 6.166 to 10.500 GHz. The computed return loss values are -14.9, -10.7, -14.3, -13.5 and -14.6 dB at frequencies 6.166, 6.833, 8.166, 9.500 and 10.500 GHz respectively. The observed VSWR values for the resonant frequency peaks are 1.43, 1.82, 1.48, 1.54 and 1.46 respectively. The values obtained for VSWR (between 1 and 2) and S11 (below -10dB) are within recommended range for the desired frequency bands. FR4 substrate is used for the fabrication of the antenna having permittivity of 4.4. The performance parameters of fabricated antenna geometry are computed using VNA tool.

본 논문에서는 스위치드 본드와이어 인덕터 뱅크를 사용하여, 넓은 주파수 튜닝범위를 갖는 다중대역 저잡음 CMOS 전압제어발진기가 제안되었다. 본드와이어 인덕터와 CMOS 스위치의 결합으로 주파수 튜닝범위는 증가하고, 위상잡음은 개선되었다. 제안된 다중대역 CMOS 전압제어발진기는 2.3GHz부터 6.3GHz까지의 주파수에 대해 동작하 며, 위상잡음은 1MHz 오프셋 주파수에 대해, 각각 -136dBc/Hz와 -122dBc/Hz를 나타내었다. 스위치드 본드와이어 인 덕터 뱅크는 각 주파수 대역에서 높은 Quality factor(Q)를 나타내어, 위상잡음과 전력소모량 사이의 trade-off를 더욱 원활하게 해 준다. 제안된 전압제어발진기는 TSMC 0.18um CMOS공정을 사용하여 설계되었고, 7.2mW의 전력을 사 용하며, 6GHz 발진주파수에 대해 1MHz 오프셋 주파수에서 -189.3dBC/Hz의 성능지수(FOM)를 나타내었다.

This paper presents a multiband low phase noise CMOS VCO with wide frequency tunability using switched bondwire inductor bank. The combination of bondwire inductor and CMOS switch transistor enhances frequency tunability and improves phase noise characteristics. The proposed multiband VCO operates from 2.3GHz to 6.3GHz with phase noise of -136dBc/Hz and -122dBc/Hz at 1 MHz offset frequency, respectively. Switched bondwire inductor bank shows high quality factor(Q) at each frequency band, which allows better tradeoff between phase noise and power consumption. The proposed VCO is designed in TSMC 0.18um CMOS process and consumes 7.2 mW power resulting in figure of merit(FOM) of -189.3dBc/Hz at 1 MHz offset from 6GHz carrier frequency.

An ultra-wideband (UWB) circular monopole antenna with a multiband-notched characteristic is proposed. The multiband-notched filter consists of three different sized folded slots, which are distinctly assigned for the notched band at the 3.5-GHz WiMAX, 5-GHz WLAN, and 8-GHz ITU bands. The proposed antenna results in a measured ${\mid}S_{11}{\mid}$ < -10 dB, which completely covers the UWB band (3.1 10.6 GHz) with three notched bands at 3.5, 5.5, and 8.0 GHz. The antenna yields an omnidirectional radiation pattern and high radiation efficiency.

We present wide-field multiband photometry of globular cluster (GC) systems toward the central region of the Fornax cluster of galaxies, including NGC 1399, NGC 1404, and NGC 1387. Observation was carried out through four optical passbands (U, B, V, and I) with the Mosaic II CCD imager mounted on the 4-m Blanco telescope at Cerro Tololo Inter-American Observatory (CTIO). This marks one of the widest U-band photometric studies on GC systems. GC candidates are selected among point sources based on their two color diagrams together with a magnitude cut. We investigate the radial variation of color distributions for the GC systems, focusing on the fundamental parameters that characterize bimodal distributions; the number ratio between blue and red GCs, the mean colors of the groups, and their color dispersions. We discuss the implication of our result regarding the origin of GC color bimodality.