A bandwidth-controllable filtering antenna based on composite effective surface plasmon polaritons (ESPPs)-substrate integrated waveguide (SIW) structure is presented. The composite ESPP-SIW structure can support ESPPs at some frequencies. The asymptotic characteristic of ESPPs is employed to form a bandpass filter, which consists of an SIW and an air cavity situated on the top of the SIW. The unequal widths and the different dielectrics of the cavity and the SIW are employed to provide flexible controllability on the dispersion of ESPPs and thus on the cutoff frequencies of the ESPPs-SIW structure. By engineering the structural dispersion of ESPPs, the filter based on ESPPs-SIW structure shows independent controllability on its cutoff frequencies and thus exhibits a controllable bandwidth. Moreover, from effective-medium aspect, an analytical method is provided to guide the filter design. The filter is used to construct a filtering antenna operating at 5G millimeter-wave (MMW). A prototype of the filtering antenna is fabricated by using multilayer printed circuit boards (PCBs). Simulated and measured results show a good skirt selectivity and flat antenna gain in the passband (22–28 GHz) and also a high suppression in the stable wide stopband (30–43 GHz).

In this letter, the stacked dual-slotted substrate integrated cavities (SICs) are proposed to achieve a filtering antenna. The dual-slotted SIC shows dual-mode behavior (quasi dual-slot mode and quasi cavity mode), which can achieve multi order response with fewer SICs. Furthermore, the antenna exists two frequencies at which the electric field has opposite horizontal component (Ex) near each slot. Thus, two radiation nulls can be obtained to enhance the frequency selectivity. The frequencies of the radiation nulls and the dual modes can both be controlled to some extent by the distance between the slots. For demonstration, a prototype at 9.65 GHz is designed with the fractional bandwidth (FBW) of 9.1%, the gain of 7.2 dBi, and the frequency selectivity of 0.70.

Coplanar plasmonic structures are proposed to converge the beam of electromagnetic (EM) wave and to enhance the gain of an antenna. The plasmonic structures are constructed by printing spoof surface plasmon polaritons (SPPs) structures on the two surfaces of a single-layer substrate. While propagating along the SPPs structures, EM wave shows a larger propagation constant than that in free space due to the slow wave feature of SPPs, i.e., the EM wave along the structures sees a higher equivalent refractive index than that of the ambient air. Equivalently, an index gradient is formed in the transverse directions, which is similar to a refractive index graded lens perpendicularly placed in front of a source antenna. To validate this concept, a millimeter wave antipodal tapered slot (ATS) antenna loaded with the plasmonic structures is designed. The antenna shows merits of beam convergence both in the E-plane and in the H-plane, although the plasmonic structures are coplanar with the E-plane, and also a wide frequency band of gain enhancement due to the non-resonant characteristic of the SPPs. Compared with the reference ATS antenna with dielectric loading, the proposed antenna shows an additional gain enhancement of 2 dBi in the band of interest (22-27.5 GHz) and the peak gain of 15.5 dBi. The measured and simulated results agree well with each other, which effectively validates the convergence effect of the plasmonic structures in the antenna.

In this letter, a differentially inserted-fed compact dual-band circularly polarized (CP) dielectric resonator antenna (DRA) is proposed. To realize a compact design, the inserted differential feeding structure composed of a pair of arc-shaped strips connecting with coaxial probes plays dual roles. It not only excites the fundamental mode HEM111 of the DRA, but also brings an additional resonant mode to form the second band. Besides, the lower and upper bands of the DRA are independently controlled by the DR and the strips, facilitating the design process of the dual-band DRA. For demonstration, a prototype is designed, fabricated and measured. Measured results show that the proposed DRA with the profile of 0.34 λ $_g$ achieves impedance bandwidth (|S $_dd$ 11|<-10 dB) of 30.4% and 18.5% and 3-dB axial ratio (AR) bandwidth of 8.06% and 6.38% with peak gain of 6.9 and 7.3 dBic for the lower and upper bands, respectively. Good agreement is observed between the simulated and measured results.

Sentiment analysis based on social media text is found to be essential for multiple applications such as project design, measuring customer satisfaction, and monitoring brand reputation. Deep learning models that automatically learn semantic and syntactic information have recently proved effective in sentiment analysis. Despite earlier studies’ good performance, these methods lack syntactic information to guide feature development for contextual semantic linkages in social media text. In this paper, we introduce an enhanced LSTM-based on dependency parsing and a graph convolutional network (DPG-LSTM) for sentiment analysis. Our research aims to investigate the importance of syntactic information in the task of social media emotional processing. To fully utilize the semantic information of social media, we adopt a hybrid attention mechanism that combines dependency parsing to capture semantic contextual information. The hybrid attention mechanism redistributes higher attention scores to words with higher dependencies generated by dependency parsing. To validate the performance of the DPG-LSTM from different perspectives, experiments have been conducted on three tweet sentiment classification datasets, sentiment140, airline reviews, and self-driving car reviews with 1,604,510 tweets. The experimental results show that the proposed DPG-LSTM model outperforms the state-of-the-art model by 2.1% recall scores, 1.4% precision scores, and 1.8% F1 scores on sentiment140.

A dual-polarized compact broadband filtering differential dielectric resonator antenna (DDRA) is proposed. For each polarization, an electric dipole is loaded on the symmetric plane of the dielectric resonator (DR) and utilized to excite the DR which further stimulates an upper dielectric patch (DP). Three differential resonances, the half-wavelength resonance of the dipole,TE ^y ₁₁₁ (TE ^x ₁₁₁ ) mode of the DR, and quasi- TE ^Z ₁₂₁ (quasi- TE ^z ₂₁₁ ) mode of the DP, are introduced into the operating band, respectively. The DP also improves the coupling degree of these resonances to obtain a broadband and flat-gain performance with high radiation efficiency. Furthermore, two radiation nulls at band edges are obtained without extra filtering circuits. The orthogonality of the degenerate modes enables dual-polarization for the design. A prototype is designed and implemented for verification.