An innovative method is proposed to improve the cross-polarization performance and impedance matching of a microstrip antenna by integrating a complimentary split ring resonator and slots as a defected ground structure. An equivalent circuit model (ECM) enables the design take into consideration the mutual coupling between the antenna patch and the Defected Ground Structure. The input impedance and surface current density analysis confirms that the integration of a CSRR within a rectangular microstrip
patch antenna leads to uniform comparative cross-polarization level below 40 dB in the H-plane, over an angular range of ± 50°. Introducing parallel slots, as well, leads to a reduction of spurious antenna radiation, thereby improving the impedance matching. Measurements conducted on a fabricated prototype are consistent with simulation results. The proposed antenna has a peak gain of 4.16 dB at 2.6 GHz resonating frequency, and hence is good candidate for broadband service applications.
Slots or defects integrated on the ground plane of microwave planar circuits are referred to as Defected Ground Structure. DGS is adopted as an emerging technique for improving the various parameters of microwave circuits, that is, narrow bandwidth, cross-polarization, low gain, and so forth. This paper presents an introduction and evolution of DGS and how DGS is different from former technologies: PBG and EBG. A basic concept behind the DGS technology and several theoretical techniques for analysing the Defected Ground Structure are discussed. Several applications of DGS in the field of filters, planar waveguides, amplifiers, and antennas are presented.
Abstract
In this paper, a circular Sierpinski shaped on-chip fractal antenna with defected ground structure (DGS) is presented for Ku-band applications. The fractal and defected ground structure are employed to achieve higher bandwidth for the entire Ku-band (12–18 GHz). The proposed on-chip antenna (OCA) with a footprint area of 4π mm2 offers wide bandwidth of 7.22 GHz (11.94–19.13 GHz) with the resonating frequency of 15 GHz. At the resonating frequency, the designed antenna shows a peak gain of −19.76 dBi and a radiation efficiency of 55.6%. The co-polarization (CP) and cross-polarization (×P) characteristics of the proposed OCA shows good isolation of 18.05 dBi and 17.44 dBi in the two principal planes with ϕ = 0° and 90° cuts respectively. The measured result of the designed OCA prototype shows a good performance over the desired frequency band.
Defected Ground Structure: Fundamentals, Analysis, and Applications in Modern Wireless Trends
