Double-layer Dielectric Substrate Research Articles

A Wideband 1-Bit Reconfigurable Reflectarray Antenna at Ku-Band

In this letter, a wideband high-efficiency 1-bit 16 × 16 reconfigurable reflectarray antenna (RRA) is proposed. First, a wideband and low loss 1-bit RRA element is designed. It consists of double-layer patches printed on two dielectric substrates, respectively, forming a multiresonant behavior to expand the bandwidth.Due to the relatively thin thickness of the double-layer dielectric substrate (0.05 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ), the element has low reflection loss. Therefore, the high efficiency and wide bandwidth performances can be obtained simultaneously. The phase difference between the two states of the RRA element is stable within 180 ± 20° in the frequency range of 12.9–16.5 GHz. Based on the broadband RRA element, a 16 × 16 RRA was fabricated and measured. Tested results show that the proposed RRA achieves 22.5% of 1 dB gain bandwidth and 25% of maximum aperture efficiency.

Ultra-wideband, optically transparent, and flexible microwave metasurface absorber

In this work, an ultra-wideband microwave metasurface absorber with optically transparent and flexible properties is proposed. The metasurface is composed of a reflective backplane and a microwave absorption layer sandwiched between two dielectric substrates. The impedance matching curves of the microwave absorption layer are deduced based on the impedance matching theory, which is quite helpful and useful to improve the accuracy and efficiency of the broadband optimization design. Simulated results show that absorption higher than 90% can be achieved in the frequency band ranging from 5.8 GHz to 27.3 GHz, which covers the radar wavebands of C, X, Ku and K. The relative bandwidth reaches up to 130%, thus realizing ultra-wideband absorption while the thickness of the metasurface is only 0.12 times the upper-cutoff wavelength. For the TE (transverse electric) wave incidence, the metasurface maintains good performance when incident angle θ ≤ 50°, while for the TM (transverse magnetic) wave incidence, the absorption higher than 90% can be still achieved in a broad frequency band when θ ≤ 60°. It can be seen that using double-layer dielectric substrate in the metasurface not only greatly expands the microwave absorption bandwidth, but also improves the oblique incident properties. In addition, the metasurface is insensitive to polarization since its unit cell is symmetrical. Moreover, by rationally designing materials, the metasurface in this work is optically transparent and flexible, thus quite suitable for window radar stealth and equipment conformal stealth.

Millimeter-Wave Butler Matrix Beamforming Circuit Using Finline in Double-Layer Dielectric Substrate

This article presents a new kind of finline in double-layer dielectric substrate and its beamforming circuit of Butler matrix in the millimeter-wave band. The finline is constructed by inserting a slotline between two dielectric substrate layers. In this configuration, it is bounded within a closed structure composed of a double-layer dielectric substrate and two rows of via-hole arrangement, contributing to low dispersion and low radiation loss of the finline characteristics. The proposed finline design aims to provide a low-complexity and low-loss transmission line which is applied to the Butler matrix design. A $4\times 4$ Butler matrix for 4 switchable beams is realized by using the finline in the double-layer dielectric substrate. In addition, a waveguide-to-finline transition is developed as a feeding circuit for the Butler matrix. Characteristics of the proposed transition and the Butler matrix were analyzed by electromagnetic analysis of the finite element method and demonstrated by experiments at 79 GHz. The proposed Butler matrix obtains a wideband characteristic and an acceptable insertion loss of 2.42 dB. The array factor which is calculated from the measured amplitude and phase outputs 4 switchable beams with the beam directions of +14°, −46.5°, +46.5° and −14°, respectively. The proposed beamforming circuit using finline in double-layer dielectric substrate would be attractive for millimeter-wave applications due to its performance and low cost.

Performance Analysis of Double Layer Stacked Patch Antenna with Edge Feed

In this paper a novel microstrip stacked patch antenna used for the Wireless LAN and Bluetooth applications is proposed. The proposed antenna is excited by using the edge feed and double layer dielectric substrate are used for enhancing the bandwidth and also for getting high gain of the antenna. The proposed antenna is simulated by using the HFSS software. The return loss up to 36.1db and gain 8.6db is obtained in the frequency range from 2.32GHz-2.38GHz with center frequency of 2.35GHz. The VSWR<1dB at center frequency of 2.35GHz is obtained.

A novel H-plane filter using double-layer substrate integrated waveguide with defected ground structures

The novel double layer substrate integrated waveguide (SIW) technology is used for realisation of conventional H-plane filter, which is manufactured in waveguide. This proposed filter is totally realised in double layer dielectric substrate with metallic vias and fabricated using a standard printed circuit board (PCB) process. In previous studies, prototypes of E-plane and H-plane filter were designed and fabricated in standard waveguides. The H-plane type of those two has the same frequency response as that of the E-plane type, while its cross section is one-quarter. Similarly, the SIW H-plane filter, which is presented in this article, has the same dispersion characteristics as that of waveguide filter while its dimensions are very shorter. Moreover, by using a sandwich model of double layer SIW, the interleaved metal vane is fabricated between two substrates easily. We can also improve the frequency response of the SIW H-plane filter using defected ground structure (DGS). Therefore, in DGS SIW H-plane filter, which is presented, the return loss and insertion loss in passband are less than conventional H-plane filter. The improvement of the spurious response is the other trait of DGS SIW H-plane filter.

Radiation Properties of Multiband Circular MSA with Half-Ring Slots

SUMMARY Novel multiband circular microstrip antennas (C-MSAs) with multiple half-ring slots are presented in this paper. Two antennafeeding systems, i.e. an embedded L-probe beneath the patch and a coplanar circular arc- shaped probe (T-probe), are used to feed the C-MSA with multiple half-ring slots. The embedded L-probe is used to excite the CMSA with a double-layer dielectric substrate due to its tremendous performance to provide a wideband impedance matching. The coplanar T-probe is proposed to realize an excellent multiband C-MSA in a single-layer structure. The C-MSA with four half-ring slots fed by the embedded Lprobe exhibits satisfactory radiation characteristics. Five frequencies with broadside radiation patterns and gains of at least 5.0 dBi are obtained. It is also confirmed by simulation that resonant frequency and gain can be easily controlled to meet the desired frequency requirements. Moreover, the C-MSA with three half-ring slots fed by the coplanar T-probe presents satisfactory performance over the four observed frequencies with good return losses (−10 dB reference). Broadside radiation patterns with acceptable cross-polarization level and gains in the range of 3.0–7.0 dBi are obtained. Couplings between the C-MSA and the coplanar T-probe have an important contribution to obtain good return losses. It can be controlled by adjusting the distance between them and the arc angle of the coplanar T-probe appropriately. Experiments of both types of antenna were conducted to verify the simulation results and good agreements are confirmed. Due to the performances, these two C-MSAs are considered to be an effective model as a

Multilayer microstrip structure analysis with matched load simulation

This paper presents a generalized approach to the full-wave analysis of multilayer microstrip structures. One of the structures studied is a new kind of microstrip bandpass filter realized in a double-layer dielectric substrate configuration. This filter demonstrates the use of the third (vertical) dimension in the design of microstrip devices. The approach involves the mixed potential integral equation technique, the Method of Moments, and an S-parameter extraction technique based on a simple form of Matched Load Simulation. Simulated and measured results for various microstrip structures are presented and show good agreement. The approach is demonstrated in detail for 2-port structures, with an outline of how it can readily be extended to the n-port case.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Suspended Slot Line Using Double Layer Dielectric

This paper presents a rigorous analysis of a) slot line on a double layer dielectric substrate, and b) slot line sandwiched between two dielectric substrates. The structure is assumed to be suspended inside a conducting enclosure of arbitrary dimensions. The dielectric substrates are assumed to be isotropic and homogeneous and are of arbitrary thickness and relative permittivity. The conducting enclosure and the zero thickness metallization on the substrate, are assumed to have infinite conductivity. The effect of shielding on the dispersion, characteristic impedance, and the effective dielectric constant are illustrated. These results should find application in the design and fabrication of MIC components and subsystems.

Suspended Coupled Slotline Using Double Layer Dielectric

This paper presents a rigorous analysis of coupled slotline a) on a double-layer dielectric substrate, and b) sandwiched between two dielectric substrates. The dielectric substrates are of arbitrary thickness and permittivity and the structure is assumed to be suspended inside a conducting enclosure of arbitrary dimensions. The odd- and even-mode dispersion and characteristics impedance, along with the effect of shielding on these, are illustrated. These structures should find extensive applications in the fabrication of MIC components, such as directional couplers, phase shifters, and mixers.