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Based on a novel microstrip terminated cross-shaped resonator (TCSR), the dual-band bandpass filters (DB-BPFs) with fixed and reconfigurable bandwidths are proposed in this brief. In addition to the basic TCSR’s three poles and four zeros, the extra four poles and three zeros can be introduced with the help of a pair of symmetrical parallel-coupled lines and open-ended stubs. Therefore, a planar DB-BPF with multiple transmission poles and zeros can be realized. To achieve the reconfigurable bandwidths, a capacitor is inserted into the basic TCSR’s lower stub. It is found that the lower bandedge of the first passband can be tuned while the other three bandedges are kept unchanged. Two prototypes, including fixed-bandwidth filter (Filter I) with 3-dB fractional bandwidths (FBWs) of 20.8% and 17.3%, and reconfigurable-bandwidth filter (Filter II) with 3-dB FBW variation from 22.5% to 34.7% for the first passband and 19.8% for the second passband, are designed, fabricated, and experimentally characterized. The experimental characterizations of these two filters verify the proposed design.

Existing smart vehicles heavily depend on success of precise positioning, optical radar, visual detection and recognition to determine their road conditions and perfect routes. The visual-based approach is the simplest and most effective enabling technology to reach the goal. In performing such an overtaking maneuver, this vision-based driving assistant system must be able to precisely recognize the lane marks first. The traditional approach needs a classifier with hand-crafted features and an adjusted threshold to achieve a robust lane detection in various environment conditions. In this paper, we adopt the deep learning approach to achieve the robust lane detection. The proposed lane detection network inspired by LaneNet model, which uses semantic segmentation concepts utilizes multiple level features of the encoder and designs enhanced binary segmentation and reduced pixel embedding branches. By reduction of computation in decoders, the proposed network effectively utilizes multilevel features to precisely predict the high quality lane maps. The experiments on Tusimple and CuLane datasets verify that the proposed lane detection network achieves better accuracy performance than LaneNet and faster computation than the existed methods for real-time applications.

Recent advances in wireless power transfer (WPT) technology enable over-the-air charging of passive sensor devices and allow sensors to be active on demand without concern of their battery lifetime. This work examines the beam pattern selection and charging power allocation problems for distributed estimation applications in wireless passive sensor networks (WPSNs) that employ WPT to replenish sensors. The charging operation consists of two-phases: an exploration phase and a replenishment-and-transmission phase. In the exploration phase, radio-frequency (RF) energy chargers first scan the network in turn using different beam patterns and sensors that harvest sufficient energy based on these beams emit pilot signals to enable channel estimation at the fusion center. In the replenishment-and-transmission phase, beam patterns and charging powers are first chosen based on the available channel state information (CSI) and then used to emit RF charging signals to replenish the sensors. The sensors utilize the harvested RF energy to make local observations of the underlying parameter of interest and transmit them to the fusion center, where the final estimate is computed. In this paper, the beam pattern selection and charging power allocation are first jointly optimized with the goal of minimizing the mean-square error (MSE) of the final estimate under perfect CSI. For tractability, an MSE upper bound is used as the objective function and the problem is solved efficiently using the block successive upper bound minimization (BSUM) method. The impact of the exploration threshold and duration on the MSE is then examined for the imperfect CSI case. Simulation results demonstrate the effectiveness of the proposed scheme.

A wideband bandpass filter (BPF) with reconfigurable bandwidth (BW) is proposed based on a parallel-coupled line structure and a cross-shaped resonator with open stubs. The p-i-n diodes are used as the tuning elements, which can implement three reconfigurable BW states. The prototype of the designed filter reports an absolute BW tuning range of 1.22 GHz, while the fractional BW is varied from 34.8% to 56.5% when centered at 5.7 GHz. The simulation and measured results are in good agreement. Comparing with previous works, the proposed reconfigurable BPF features wider BW tuning range with maximum number of tuning states.

In this paper, we propose a data-dependent transmission control policy over the slotted ALOHA MAC protocol and a cross-layered fusion rule that exploits MAC timing information for distributed detection in sensor networks. In this system, each sensor first makes a local decision at the beginning of each observation period and transmits the decision to the fusion center over a random access channel. Based on the slotted ALOHA random access protocol, we propose a class of data-dependent transmission control policies that assign to sensors their transmission probabilities according to the reliability of their local decisions. For the case with i.i.d. observations in each time slot, we show that the optimal transmission control function takes on the form of a thresholding function. That is, a sensor will transmit in a given time slot if and only if its local log-likelihood ratio exceeds a certain threshold. When observations are made only every several time slots, the message arrival time at the fusion center, which is spread over the observation period of duration K > 1, will embed the reliability of the received sensors' decisions as a result of the data-dependent transmission control. This timing information can be accounted for in the fusion rule to further enhance performance. Finally, we extend the proposed strategies to multicluster sensor network scenarios, where the sensors' local decisions are transmitted to the fusion center in a two-hop fashion. We show, through numerical simulations, that the proposed schemes outperform both conventional slotted ALOHA and TDMA-based schemes that do not adopt cross-layered transmission and fusion strategies.

A substrate-free 160 times 160 focal-plane array (FPA) with a 60-mum times 60-mum pitch has been developed and used for an optical readout uncooled infrared (IR) detector. The supporting frame of the FPA is a temperature-variable one due to its large decreases in both heat capacity and thermal conductance. This thermal characteristic significantly increases the temperature change of the microcantilever, which depends on both the temperature change induced by its absorption of IR radiation and the linear superposition of the temperature prechange induced by other microcantilevers, and therefore improves the performance of the substrate-free FPA. In the proposed IR detector, the fabricated FPA had an average noise equivalent temperature difference (NETD) and a response time of 330 mK and 16 ms, respectively. Its performance increased by about 4.3 times compared with that of the substrate FPA that consists of the same microcantilevers.

A beamspace-time (BT) receiver is proposed for interference suppression and multipath diversity reception in sectored wireless code division multiple access communications. The scheme involves two stages. First, a set of adaptive space-time diversity processors, in the form of beamformer-correlator pairs, is constructed which provides effective suppression of unwanted interference and reception of signals from a prescribed space-time region. Second, the output data obtained by these processors are maximum ratio combined to capture the signal multipath components coherently. The proposed BT receiver is blind in that no training signal is required. The only information required is the signature sequence, timing and a rough estimate of the angle of arrival of the signal for selecting the sector of interest.