In this paper, a novel planar active artificial magnetic conductor (AAMC) frequency-reconfigurable antenna printed on an FR4 substrate is proposed. Its AAMC metal pattern in a unit cell consists of a compound-five-ring nesting (CFRN) structure. It is loaded with only one varactor diode connected to the ground plane by a metallic via. In comparison to the conventional single-circle-ring AMC, the dimension of the CFRN-AMC has been reduced by about 44% along with a lower reflection loss. The frequency-reconfigurable antenna is constructed by placing a triangle-shaped dipole antenna operating at 1.8 GHz over the proposed active CFRN-AMC ground plane consisted with 5×5 periodic unit cells. The prototype of the CFRN-AMC-backed antenna was fabricated and measured. The measured results agree well with the simulated data. It is found that by tuning the capacitance applied on the CFRN-AMC from 2.2 to 0.5 pF, the frequency band of the AMC-based antenna has been varied in the range of 1.51 through 2.12 GHz along with the highest radiation gain of 5.37 dBi at 1.74 GHz. This gain is about 3.16 dB higher than that of the antenna without using the AMC. In addition, the presented CFRN-AMC-based antenna remains a very low profile, since the separation distance between the antenna and the AMC plane is only 2 mm or 0.012λ, where the λ denotes the wavelength at 1.8 GHz in free space.

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Design of a Low-Profile, Frequency- Reconfigurable, and High Gain Antenna Using a Varactor-Loaded AMC Ground

A microstrip monopole antenna backed with a novel uniplanar compact electromagnetic bandgap (UC-EBG) structure for 2.4 GHz wireless body area network applications is proposed here. The proposed antenna has a size reduction of 50% when the number of EBG array is optimised from 3 × 4 to 2× 3, while the radiation performance is almost invariable at the same time. The operating frequency band under different conditions has the capability of covering the 2.4–2.4835 GHz industrial, scientific, and medical band. Due to the addition of 2×3 UC-EBG on the back, the radiation patterns become unidirectional, and the measured average gain increases from 2.1 to 5.6 dB. Meanwhile, the cross-polarisation of the monopole antenna can be suppressed prominently by the EBG array. The simulated specific absorption rate values are 0.0536 W/kg under 1 g standard and 0.0296 W/kg under 10 g standard, which are far below the limitation of USA and Europe. These results can manifest the reliable wearable performance of the proposed antenna.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-map.2019.0271

Microstrip monopole antenna with a novel UC-EBG for 2.4 GHz WBAN applications

In order to realize the ultrawideband suppression of simultaneous switching noise (SSN), a hybrid-embedded novel electromagnetic band-gap (EBG) structure is proposed. The presented EBG structure is based on the traditional Z-bridge EBG embedded the L-bridge EBG structure. By the HFSS software simulation and real test, the results show that the proposed EBG structure can obtain ultrawideband suppression of SSN. Compared with the traditional Z-bridge and L-bridge, the suppression effect is greatly improved. This paper analyzes the reason that the new structure can achieve ultrawideband suppression of SSN based on the equivalent circuit model of the structure. Moreover, the proposed structure will lead to signal integrity problems, which is analyzed by eye diagrams.

Hybrid-Embedded EBG Structure for Ultrawideband Suppression of SSN

A novel electromagnetic bandgap (EBG) power plane etched with multiring complementary split ring resonators (CSRRs) is proposed for effectively suppressing simultaneous switching noise. Its equivalent circuit model is derived for predicting its bandwidth numerically. The measured insertion losses, i.e., S21-parameters of the two fabricated samples agree well with the simulated ones obtained by using the commercial software HFSS, respectively. It is shown that –40 dB suppression is achieved over an ultrawideband from 600 MHz to 13.26 GHz, when the two-ring CSRRs EBG power plane is used. While for four-ring CSRRs EBG case, the suppression level can be extended to –60 dB. Comparative studies are also performed on the signal integrity of a pair of differential transmission lines over L-bridge EBG with and without CSRRs, respectively, and similar performance is achieved.

A Novel Electromagnetic Bandgap Power Plane Etched With Multiring CSRRs for Suppressing Simultaneous Switching Noise

This paper presents a periodic electromagnetic bandgap (EBG) structure in the integrated fan-out wafer-level package (InFO-WLP) technology for gigahertz-band noise suppression. The proposed EBG structure consists of an $LC$ resonator with two symmetrical spiral inductors in series and a shunt metal–insulator–metal capacitor between power and ground planes. The third-order equivalent model of the EBG structure is also proposed and extracted by field solver ANSYS Q3D to model the performance. In addition, the EBG arrays with different sizes of unit cell and the corresponding stopband bandwidth and isolation were characterized. The measurement results show that the proposed $1 \times 4$ EBG array of 600- $\mu \text{m}$ square unit cell can achieve a 29.5-GHz stopband bandwidth together with an over 30-dB isolation level. Furthermore, by using the InFO-WLP technology, the proposed EBG structure is integrated with an RF low-noise amplifier (LNA) fabricated in a 16-nm FinFET technology as a case study to validate the power noise immunity. The experimental results show that the measured output spectrum of LNA integrated with the proposed EBG structure at the power plane can suppress the noise tone from −37.37 to −68.65 dBm.

An Electromagnetic Bandgap Structure Integrated With RF LNA Using Integrated Fan-Out Wafer-Level Package for Gigahertz Noise Suppression

In the paper, a novel structure for suppressing simultaneous switching noise is proposed based on the coplanar electromagnetic bandgap (EBG) power plane. The proposed EBG structure is designed on the basis of periodic L-bridge which is inserted by a small L-bridge cell with windmill-shaped slits where the power port is located. Simulation and measurement results show that the presented structure possesses a wide stop band ranging from 510 MHz to 10.35 GHz at −40 dB suppression of the bandgap depth. Then, the IR drop and the dc resistance are accurately investigated by the simulation software of CST. Finally, time-domain simulation results show that the structure in high-speed circuit is met with signal integrity.

Novel L-EBG Embedded Structure for the Suppression of SSN

The invention discloses a calculating circuit for output current under a DCM (discontinuous conducting mode) of a flyback PWM (pulse width modulation) converter, and mainly solves the problem that the existing flyback PWM converter is large in output current error. The calculating circuit comprises a sequential circuit (1), a peak detection circuit (2) and a current calculation circuit (3), and the sequential circuit (1) provides control sequences to the peak detection circuit (2) and the current calculation circuit (3); the peak detection circuit (2) provides sampled peak information of primary-side inductor current of the inverter to the current calculation circuit (3); the current calculation circuit (3) outputs voltage having a linear relation with output current of the flyback inverter by calculating the inverter primary-side inductor discharge time and inverter primary-side inductor peak value. Power consumption and area of the circuit are reduced, output current of chips can be detected, and the calculating circuit can be used for design of analog integrated circuits of power supplies.

Kai-Jing Li

Papers

Novel L-EBG Embedded Structure for the Suppression of SSN

Calculating circuit for output current under DCM (discontinuous conducting mode) of flyback PWM (pulse width modulation) converter