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In this letter, two novel broadband circularly polarized slot-microstrip antennas (SMPA) with circular and square structures are elaborated. The circular SMPA is composed of four crown patches as parasitic elements, four crown slots etched on a circular ground plane, and a circular loop sequential phase feeding structure. However, the square SMPA consists of four parasitic rectangular patches, four square slots with cut corners, and a square-loop feeding structure. In the circular SMPA, the parasitic crown patches and crown slots are used to excite multiple circularly polarized (CP) resonant modes, which are fed by a circular loop sequential phase feeding structure through capacitive coupling. Combined with these CP modes, the CP bandwidth of the presented antenna could be improved. Eventually, the proposed circular SMPA has a broad 3-dB axial ratio bandwidth (ARBW) of 20.6% (5.206.40, 5.8 GHz) and a wide 10-dB impedance bandwidth (IBW) of 25.8% (4.926.38, 5.65 GHz), which could occupy the WLAN (5.7255.85 GHz), ITS (5.8 GHz), and WIFI (5.85-5.925 GHz) bands.

In this paper, systematic characterization of the dual probe, which is designed for the near field simultaneous measurement of both electric and magnetic field, is investigated with a microstrip line as the device under test (DUT). The characterization includes frequency response, transmission performance, symmetry, reflection, the intrusion of probe to the DUT, isolation of electric and magnetic field responses, field profile and spatial resolution, and differential electric field suppression. The dual probes with different design are adopted to demonstrate the systematic characterization.

An extended model of through-silicon via (TSV)-based solenoid inductor is proposed to save on-chip areas for 3-D radio frequency (RF) ICs and package integration. To achieve a high inductance density, the nested topology consists of high-density TSVs in high-resistivity silicon substrate and multilayers of metals in compatible CMOS process. Then, an analytical inductance model, considering the mutual inductance of TSVs and complicated metal traces, is established and verified. The inductance variation in physical dimensions is studied based on the modeled and simulated results of a TSV solenoid inductor in single tier. The proposed TSV solenoid typology gets better performance at inductance density and quality factor around some frequencies through analytical model and full-wave simulations. Further studies are directed toward RF application overview according to broadband and low power consumption.

Recent studies reported that PIG negative hydrogen ions extraction for neutron tube is superiority to positive hydrogen ions extraction. Present maturing products of neutron tube on market almost use PIG ion source and extract positive hydrogen ions. If negative hydrogen ions extraction can be applied on present products, the combination property will be greatly improved. In this study, a contrast experiment of PIG positive and negative hydrogen ion source for D–T neutron tube is put into effect. The relationships between the current of ion source, the beam current and the voltage extraction are investigated. The experiment results demonstrate that the negative ion extraction has higher yield of neutron for unit target current. We also point out that the ratio of yield to target current is a considerable parameter to reflect the overall performance of neutron tube.

Radio-frequency interference (RFI) problems in modern electronic product become complex which result in the increasing number of scanning points. Conventional near-field phaseless source reconstruction methods such as double planes iteration method and single plane iteration method will spend a lot of time in both scanning and calculating. To save the calculating time and scanning time, an alternating iterative method is proposed for source reconstruction based on magnitude-only and single-plane near field scanning. Firstly, the single-plane scanning data is divided into two groups as group A and B according to the components, i.e. the electric field group and the magnetic field group for the four components, or ${H_{x}}$ group and ${H_{y}}$ group for two components. Then, the processed A and B phaseless data groups are used iteratively in the back-and-forth transformations to get the equivalent dipole elements. Under the premise of a large amount of scanning data, such as the simulation example, compared with conventional method filling the scanning data into a whole matrix, the proposed method can save 90% calculating time, especially the time in singular value decomposition (SVD) before the iteration. A numerical simulation and a measurement example is verified the effectiveness of the proposed method, which show a comprise between accuracy and efficiency.

Electromagnetic patterns in near field scanning usually give important information about the source inside an device under test. In this paper, we develop a postprocessing technique, including standard-deviation-based method, principal component analysis, and K -means method, so that the electromagnetic patterns in near field scanning can be extracted fast and grouped automatically and efficiently. The postprocessing techniques are applied to experimental near-field scanning of ICs, such as a microcontroller unit (MCU) and a field programmable gate array (FPGA). The grouping on the electromagnetic patterns of the MCU is in good agreement with the published grouping result, and the grouping on the electromagnetic patterns of the FPGA can find out the additional cluster responsible for additional circuit.

To measure the magnetic near field with high common-mode noise rejection, a probe with the differential and symmetrical structure forming a detection loop is developed. Such measurement is performed by using a two-port vector network analyzer (VNA) and validated by using a microstrip line as a device under test (DUT). In comparison to the measurement with traditional single-output magnetic near field probe, the electric field suppression of the proposed measurement can be improved by at least 10 dB in the frequency range of $3\sim 11$ GHz, while the other characteristics remain unchanged.

In this paper, the radiated emission of a microcontroller integrated circuit is investigated by rotating the test board in a transverse electromagnetic (TEM) cell measurement. The dependence of the radiated emission on the angle of rotation is derived on the basis of the coupling between a microstrip line and the TEM cell, and then validated by the multiple-orientation TEM cell measurements in a quantitative accuracy of fitting. With the validated dependence, the radiated emissions contributed by electric and magnetic coupling are extracted. The extracted emissions are found in agreement with the measurement result by near-field scanning experiments.

With the trend of miniature, high-integrated assembly modules are common in modern industry. The measurement of the flowing current and voltage on a trace is basic for diagnosis and monitoring of these modules. The traditional contact detection method is not practical especially in conditions of high power and small space. In this paper, we demonstrate a novel method for collocated and simultaneous measurements of radio frequency current and voltage on a trace in a noncontact and movable manner. The measurements are achieved by using a compact probe with both voltage and current detectors, as well as an algorithm based on the transfer functions quantifying the capacitive and inductive couplings between the detectors and the tested trace. The proposed method is verified and applied for continuous power measurements, collocated and simultaneous measurements of transient voltage and current pulses and the dynamic voltage and current of a switching device.

A near-field scanning is usually time-consuming to map the electromagnetic field along the surface of a device. In this communication, a dual probe is proposed with a U-shaped loop to sense radio frequency (RF) magnetic and electric fields simultaneously, so that the one-time scanning by the dual probe can replace the two-time scanning by single-detector probes. Different from the traditional near-field scanning by using a single-detector probe and spectrum analyzer, the proposed scanning can be achieved by the two-output probe and a two-port vector network analyzer connecting to the probe. The efficient near-field scanning measurements of the electric and magnetic field on a conductor-backed coplanar waveguide transmission line and an RF power divider by using the dual probe are in agreement with those by using two single-detector probes.

Hexagonal ground-shielding through silicon vias (TSVs) in 3D ICs are explored based on measurement and simulation. The measured S-parameters of the TSV-bundle part are successfully extracted by de-embedding technique. The results math well with simulations up to 20GHz. The proposed TSV bundle has a good performance of return and insertion loss. For the hexagonal ground TSV shield system, the crosstalk analysis of neighbor signals in the TSV shield system is made based on the measurements and simulations. The electronic and magnetic field plots show a good capacitive and inductive coupling isolation for the victim signal TSV with shielding ground TSVs. Compared to those coupled-TSVs systems without ground guide, the ground-shielding TSV as well as coaxial TSV has higher noise over the range of frequencies.

This paper presents a noncontact radio frequency voltage sensing of a printed trace by using a capacitive-coupled probe. The noncontact voltage sensing is demonstrated by using an open-end coaxial probe, and achieved through the transfer factor from the printed trace to the probe and a reconstruction algorithm. To validate the voltage sensing, known periodic, and pulse voltages are injected into the printed trace and compared with the reconstructed waveforms. Our results demonstrate that the voltage sensing method can be used for measurement of a random waveform with period even down to 1 ns and single pulse with rise time down to 2 ns. In consideration of the flexible relocation of the probe, the voltage sensing accuracy caused by spatial errors is also investigated.

Degradation characteristics and mechanisms of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated under swift heavy-ion irradiation. AlGaN/GaN HEMTs were exposed to 800 MeV Bi ions with fluence up to 5.28 × 10 10 ions/cm 2 . Post-irradiation measurement shows that the saturation drain current reduced by 15%, the maximum transconductance decreased by more than 27%, and both the positive and negative gate characteristics degraded dramatically. By the off-state examination using the Photo Emission Microscopy (PEM), electroluminescence hot spots were found in the gate areas, which indicates new leakage passages produced by heavy-ion bombardment. Micro cross sections were prepared at hot spot areas by dual-beam focused ion beam (FIB) and examined using transmission electron microscope (TEM). The presence of latent tracks throughout the whole hetero-junction area was confirmed. Latent tracks, which related to the high density ionizing energy-loss, play a role of new leakage paths and account for the increment of gate leakage. Moreover, nonionizing energy-loss induced defects decrease the charge density in the two-dimensional electron gas (2DEG) and reduce the carrier mobility, leading to the degradation of device output performances.