This article presents a compact 24–30-GHz four-element phased-array transceiver (TRx) front-end (FE) for 5-G communications. A compact T/R switch co-designed with power amplifier’s (PA) output matching network and low-noise amplifier’s (LNA) input matching network is proposed. Leveraging the transformers in the two matching networks, only one extra transistor switch is needed, which greatly reduces the chip area consumption and therefore the insertion loss. A bidirectional phase shifter composed of a two-stage polyphase filter (PPF) and two bidirectional variable-gain amplifiers (BVGA) is shared by both TX and RX. The 24–30-GHz four-element TRx FE is implemented in 65-nm CMOS process. The TX path including the power splitter and T/R switch achieves a measured 11.5-/16.5-dBm OP1dB/PSAT with 12.2%/22.9% PAE$_{\mathrm {1 dB}}$/PAEMAX with 35.1-dB gain. The RX path including power combiner, T/R switch, and off-mode PA achieves a minimum 5.1-dB noise figure (NF) with 25.8-dB gain. The TX and RX paths achieve 5.625° phase resolution with$ < 2^{\circ }$/0.4-dB rms phase/gain error as well as 30.6-dB gain control range with 0.5-dB gain step and$ < 1.5^{\circ }$/0.26-dB rms phase/gain error over 24–30 GHz. Under the 64-QAM fifth-generation (5G) NR FR2 orthogonal frequency division multiplexing (OFDM) measurements, the TX path achieves an average output power of 0 dBm per element (2.1% PAE) with 8.66% EVM, and the RX path achieves an average 4.96% EVM, making the proposed TRx FE suitable for 5G NR FR2 applications. The chip size excluding pads is$4.1\times4.0$mm.

In this paper, an automated tracking system with head and tail recognition for time-lapse observation of free-moving C. elegans is presented. In microscale field, active C. elegans can move out of the view easily without an automated tracking system because of the narrow field of view and rapid speed of C. elegans. In our previous works, we constructed an automated platform with 3D freedom to track centroid region of the nematode successfully. However, tracking time was not long enough to support a full time-lapse observation. Our proposed system in this study integrate the detection method in horizontal plane with depth evaluation more tightly. Tracking time and response speed have been greatly improved. Besides, we make full use of curvature calculation to make the system recognize the head and tail of C. elegans and the recognition rate can be up to 95%. The results demonstrate that the system can fully achieve automated long-term tracking of a free-living nematode and will be a nice tool for C. elegans behavioral analysis.

We have successfully achieved manipulation and assembly of microbeads having the size of 100μm diameter by hemispherical end-effectors with high stability and accuracy. The motivation of achieving assembly of actual cells lies in the great significance of it in tissue regeneration and cell analysis. Firstly, the most difficult problem we need to solve is the releasing problem caused by adhesion force. The viscosity on cell surface is much larger than the microbeads which makes cell releasing challenging. Secondly, the cell can generate its deformation, then contact area with end-effector will change during grasping process. This may influence the adhesion force and also bring problem to releasing. Thirdly, cell is much smaller, around 15μm in diameter, so we need to fabricate smaller end-effector to achieve successful manipulation and ensure the stability in the meantime. In this paper, we realize the manipulation by decreasing the adhesion forces and apply vibration to release a cell stably. We found the appropriate scale size for the end-effector is around 10μm diameter. It can not only grasp a 15μm cell but also bring little interference to the environment. As a demonstration of the proposed manipulation method, the repeated experiments were conducted to explore the dependence of adhesion force on the grasping distance, which can be helpful in the improvement of successful rate. Finally, we achieved automatic cell assembly using Hela cells.