A miniaturized substrate integrated waveguide (SIW) bandpass filter with an area of 0.682×0.210 mm2 is proposed based on Through-Silicon Via (TSV) technology for terahertz (THz) applications. The design method of the THz cavity filter based on rectangular TSV is introduced and the filtering characteristics are investigated by the finite element method (FEM) and mode matching method (MMM). The rectangular TSV is substituted by cylindrical structures and the THz cavity filter is fabricated and measured in order to investigate the possibility of integration with typical 3D IC manufacturing processes. The cavity filter utilizing cylindrical TSV exhibits a bandwidth of 0.051 THz centered at 0.331 THz, an insertion loss of 1.5 dB, and a reflection of higher than 15 dB in the passband.

This letter presents a compact, low-loss flexible filter based on a double-interdigital coupling stepped-impedance resonator (SIR) and through-polyimide via (TPV) technology. With a fractional bandwidth (FBW) of 12.5% at 2.5 GHz, the filter achieves a low insertion loss of 1.8 dB in the flat state and only 1.95 dB under bending. Its electrical performance remains highly stable under deformation, while the structure attains a 40% size reduction over the state-of-the-art designs, offering a promising solution for wearable wireless systems demanding flexibility and spectral selectivity.

The electromigration (EM) can introduce voids and hillocks in through-silicon vias (TSVs) and redistributed layer (RDL) interconnects, increasing the risks of short-circuit and open-circuit failures and thereby severely affecting the reliability of chiplet systems. In this article, the EM failure mechanism of the interconnects under electrical–thermal–stress multiphysics coupling is investigated, and a novel method for EM lifetime prediction based on coupled multiphysics modeling and finite element simulation is proposed. The implementation of dynamic failure simulation through element activation/deactivation technology employs a 20% void area ratio as the interconnect failure criterion, allowing for quantitative lifetime prediction. The consistency between the experimental and simulation results demonstrated the accuracy and effectiveness of the proposed lifetime prediction method. The overall prediction error is reduced by 11% with the state-of-the-art EM prediction method. Furthermore, based on this method, the effect of different interposer materials and TSV radii on interconnect EM is investigated. The evidence exhibits that using diamond as an interposer material can significantly mitigate interconnect EM phenomenon and enhance the reliability of the whole structure compared with silicon and glass. Furthermore, increasing the radius of TSV enhances EM resistance in interconnects, with each $1~\mu $ m increase in radius extending the average interconnect lifetime by 12.75 h. Finally, the sensitivity analysis of diffusion-related constants further validates the robustness of the proposed model to critical parameters.

Transformers are the key passive devices in many radio frequency integrated circuit (RF IC) applications. In this paper, a kind of ultra-high coupling coefficient and symmetric transformer based on through-silicon via (TSV) is proposed. HFSS software is used to model and simulate the transformers with turn ratios of 1:1, 1:2 and 1:3, and the three structures are manufactured and measured. The measurement results show that the coupling coefficients of the three are 0.956, 0.971 and 0.954, and the areas are 0.007 mm ² , 0.012 mm ² and 0.015 mm ² . Compared with other literatures, it has the characteristics of high coupling and miniaturization.

A compact branch line coupler with lumped elements on silicon substrate is realized by employing through-silicon via (TSV) technology, in which the lumped elements adopt high-density, high-Q three-dimensional solenoid inductors and double-layer interdigital capacitors. And the proposed coupler is fabricated and measured. The results show that, the return loss of the coupler is less than -19.7 dB, the isolation is less than -15.2dB at 4.7~5.3GHz, and the phase imbalance within the operating frequency range is within ± 1.2°. In addition, the size of the branch line coupler is only 1.2×1.36mm²(0.069×0.078λ_g²).

We present a flow cytometer on a microfluidic chip that integrates an inline lens-free holographic microscope. High-speed cell analysis necessitates that cells flow through the microfluidic channel at a high velocity, but the image sensor of the in-line holographic microscope needs a long exposure time. Therefore, to solve this problem, this paper proposes an S-type micro-channel and a pulse injection method. To increase the speed and accuracy of the hologram reconstruction, we improve the iterative initial constraint method and propose a background removal method. The focus images and cell concentrations can be accurately calculated by the developed method. Using whole blood cells to test the cell counting precision, we find that the cell counting error of the proposed method is less than 2%. This result shows that the on-chip flow cytometer has high precision. Due to its low price and small size, this flow cytometer is suitable for environments far away from laboratories, such as underdeveloped areas and outdoors, and it is especially suitable for point-of-care testing (POCT).