A high efficient 915 MHz rectenna is designed using a harmonic rejection low pass filter (LPF). The proposed rectenna consists of a slot coupled dipole antenna and high order harmonic rejection LPF, voltage doubler type rectifier, a LPF for the DC path, and resistive load. The use of a 2 nd and 3 rd harmonic rejection LPF in the rectenna results in high conversion efficiency. Performance of rectenna is analyzed using harmonic balance analysis. The proposed rectenna achieves a RF to DC conversion efficiency of 74.8 % when the received RF power is 62.2 mW. The maximum output DC voltage across R L was 7.2 V at a distance of d = 50 cm from the transmitter and the possible maximum transmission distance can be achieved by 2 m at steel box girder type Gimpo Bridge
This paper presents a low power discrete-time receiver supporting three broadcast services FM, T-DMB and DAB. To meet the requirement of sensitivity, three LNAs are implemented to cover each band. The proposed mixer core is terminated by a common-gate current buffer to improve linearity and merged with a switched-capacitor sampled filter in current mode for low power and low complexity. The filter performs the second-order low-pass filtering with anti-aliasing ratio up to 70 dB at 1.6 MHz bandwidth. The chip is fabricated in a 90 nm CMOS technology and dissipates 11 mA current from 1.2 V supply. The receiver shows 48 dB maximum gain, 60 dB gain control range, 2.7 dB noise figure, and -22/0 dBm IIP3 in LNA high/low gain mode.
This paper presents an eight-channel inverter transimpedance amplifier (INV-TIA) array realized in a standard 0.18μm CMOS technology for the applications of linear laser detection and ranging (LADAR) systems. For comparison purposes, a couple of multi-channel TIA arrays including a four-channel current-mirror transimpedance amplifier (CM-TIA) array, and a four-channel INV-TIA array are demonstrated together.A typical linear LADAR system mandates a compact high-speed read-out integrated circuit (ROIC) to capture the reflected lights from a target. Therefore, the design approach of a conventional current-mode TIA is an easier way. However, the crosstalk performace between channels of the current-mode TIAs gets seriously detrimental in accordance with increasing frequencies. Hence, we exploit a voltage-mode INV-TIA array in this work so as to lower the crosstalk between channels for comparable gain, bandwidth, and power consumption characterstics.
We seek closed form s equilibrium probability distribution of closed reentrant Lu-Kumar network buffer priority policies. For the last b (LBFS) policy, an explicit closed form is first buffer first served (FBFS) policy, su exists for us to obtain expressions for m reduced dimension Toeplitz matrix mus for a complete solution. We use the resu throughput and asymptotic losses of the s Distribution ority Policies rk.
As the deformation behaviors of hair strands vary greatly depending on the hairstyle, the computational cost and accuracy of hair movement simulations can be significantly improved by applying simulation methods specific to a certain style. This paper makes two contributions with regard to the simulation of various hair styles. First, we propose a novel method to reconstruct simulatable hair strands from hair meshes created by artists. Manually created hair meshes consist of numerous mesh patches, and the strand reconstruction process is challenged by the absence of connectivity information among the patches for the same strand and the omission of hidden parts of strands due to the manual creation process. To this end, we develop a two‐stage spectral clustering method for estimating the degree of connectivity among patches and a strand‐growing method that preserves hairstyles. Next, we develop a hairstyle classification method for style‐specific simulations. In particular, we propose a set of features for efficient classifications and show that classifiers trained with the proposed features have higher accuracy than those trained with naive features. Our method applies efficient simulation methods according to the hairstyle without specific user input, and thus is favorable for real‐time simulation.
Jun-young Yoo․Byeong-gyu Park․Sang-gyun Kim*․Seung-hwan Jung*․Yun-seong Eo 요 약
IntroductionRecently, the increasing interest in watching TV in a mobile environment makes it necessary to integrate TV on a hand-held device. The traditional TV receiver modules (called tuner), which are not appropriate for a mobile device, consume too much power and use too many off-chip components. Thus, in order to integrate TV receiver into a mobile device, power consumption and size should be reduced dramatically. The system on a chip technology, which integrates all of the functional blocks including the digital part on a single chip, can be the best solution for those requirements. The proposed architectureUsually, TV tuner has complicated structure that consumes relatively high power. It has image rejection filter in the heterodyne structure or complicated poly-phase filter in the low-IF receiver. However, such structures are not adequate to be adopted in the low power and small size mobile TV tuner. To overcome this limitation, the direct conversion structure satisfying the requirements of low power and DVB-H standards is adopted in this paper. Figure 1 shows the proposed dual band RF front-end which consists of two LNAs, single to differential (S/D) converter, passive mixer, and TIA with LO buffer. The proposed architecture can receive dual band signals, such as UHF (470MHz ~ 862MHz) for DVB-H and L-band (1670MHz ~ 1675MHz) by employing two separate LNAs. Also, integrated single to differential converter acts as a function of external balun to reduce noise figure. In the direct conversion system, the down-converted signal at base band is vulnerable to flicker noise which is inversely proportional to frequency. The traditional Gilbert cell mixer is known to generate flicker noise at the cross-over point, when the steering transistors are both in the 'ON' state and their flicker noise is visible at the output [2]. In this paper, an alternative approach of passive mixer is used since there is no inherent flicker noise, when the switch mixer is used in an AC coupled fashion. Thus, the passive mixer and TIA are adopted to solve these disadvantages. The RF front-end gain and linearity are optimized by design technique of passive mixer that can achieve high linearity and low flicker noise for direct conversion RF front-end. The design of RF front-end A. UHF LNA and L band LNAThe most important features of LNA are low noise and high gain to reduce the input referred noise contribution of the subsequent stages, and high linearity: typically measured in terms of the input referred third-order intercept point, IIP3, to accommodate high input signal and strong interferer. The UHF LNA for DVB-H should cover wide band input frequency range (470MHz ~ 862MHz) while maintaining input matching, noise figure and linearity performance. Therefore, as shown in figure 2, resistive shunt feedback cascode common 978-1-4244-2642-3/08/$25.00 ©2008 IEEE source (CS) topology is applied. In figure 2, LG and PD mean low gain mode and power down mode, respectively. When the input signal is large, the RF front-end has a limitation of ...
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