Compact four-band diplexer using defected ground structures

In this paper, a novel four-band diplexer using defected ground structures with compact size, low insertion loss and high isolation is presented. To begin with, there are 16 defected ground stepped impedance resonators (DSIRs) controlling four passbands characteristics. Every four DSIRs can generate one passband. Then, four different DSIRs use the same feeding line. According to the group delay, we can determine the relative physical position of the first resonator. For the demonstration, a four-band diplexer operating at 2.45/4.2 and 3.5/5.2 GHz with the fractional bandwidths of 10, 7, 6.2 and 5% is designed and fabricated. Finally, measured results agree well with simulated results.

Electrical Size Reduction of Microstrip Antennas by Using Defected Ground Structures Composed of Complementary Split Ring Resonator

In this study the effects of using defected ground structures (DGS) composed of a complementary split ring resonator (CSRR) and CSRR with dumbbell (CSRR-D) for rectangular microstrip antennas are investigated. On this aim, two different antennas, which are Antenna B having CSRR etched DGS and Antenna C having CSRR-D etched DGS are designed and fabricated in comparison with the ordinary rectangular patch antenna, which is Antenna A. In both Antennas B and C, CSRR structures are etched in the same position of the ground planes. On the other hand, another ordinary microstrip antenna, called Antenna D, is designed at resonance frequency of Antenna C. For the characterization; resonance frequencies, voltage standing wave ratios, percentage bandwidths, gains, ka values and gain radiation patterns are investigated both in simulations and experiments. The numerical analyses show that 29.39% and 44.49% electrical size reduction (ESR) ratios are obtained for Antenna B and Antenna C, respectively in comparison to Antenna A. The experimental results verify the ESR ratios with 29.15% and 44.94%. Supporting, Antenna C promises 68.12% physical size reduction (PSR) as it is compared with Antenna D. These results reveal that Antenna C is a good alternative for DGS based microstrip electrically small antennas.

Tri-Band Slot-Loaded Microstrip Antenna for Internet of Things Applications

A new design of a multiband microstrip patch antenna using slots in the patch as well as defected ground structures (DGS) implemented in the ground plane is proposed. Multi resonance response was obtained by etching the DGS shapes in the ground plane of a Traditional patch operates at 5.2 GHz, which is the common frequency for the Internet of Things (IoT) applications. The novel outcome of this work is a compact antenna that resonates at three bands, viz. 2.42, 5.22 and 5.92 GHz. Different shapes of slots were used to improve the antenna performance at the different resonances. The antenna used the inset feeding technique to improve impedance matching. Rogers RO3003 substrate of 3 relative dielectric constant, 0.0013 loss tangent, and 1.5 mm thickness was used to build the antenna. The designed antenna was simulated using HFSS software. The good consistency between simulations and measurements confirmed the antenna's ability to improve the benefits for IoT applications at the three different frequencies.

Design of Dual Frequency Coupled Resonators Using DGS and Microstrip Resonators for Dual Band WPT Applications

This paper introduces a new design for a highly efficient and more compact size dual frequency wireless power transfer (WPT) system, which can operate at both 0.65 GHz and 1.56 GHz bands. The idea of the structure depends on designing a symmetrical system containing Tx and Rx. Each Tx and Rx has a feed line on the top layer with two stubs; each stub has different dimensions than the other one. The bottom layer contains two C-shaped defected ground structures (DGS). By changing the dimensions of one stub, the frequency resonance corresponds to this stub is changed without any change on the other resonance. The system has a size of 20 × 20 mm2. Further, the system achieves efficiencies of 72 % and 89 % at 0.65 GHz and 1.56 GHz, respectively with a transmission distance of 8 mm. The proposed dual frequency WPT is implemented and verified. Good concurrences among electromagnetic (EM) simulations and the measurements have been attained. The system is suitable for recharging shortrange applications.