Mushroom Electromagnetic Band Gap Structure Research Articles

Metamaterial Properties Applied in Wire Antenna Design

In this paper, metamaterials are used, in order to verify their utilities; two different structures have been considered as a ground. The first one is a mushroom EBG (Electromagnetic Band Gap) structure which is composed of several patches with a ground connecting via, where the second one is a 2D metamaterial structure with resonant rings and digital capacitors. CST, which is based on one of the most popular numerical method Finite-Difference Time-Domain (FDTD) is used. Both the structures are investigated by simulation and compared at the frequency of 12 GHz, the metamaterials properties are successfully verified around the resonant frequency. A very low cost wire is transformed into a valuable circuit by enhancing the directivity and the gain in order to rival other antennas, in order to ensure a large use to the dipole. The digital capacitor has essential part in this work. The antenna proposed in this work is in the frequency band Ku.

High-Gain Patch Antenna Based on Cylindrically Projected EBG Planes

One kind of artificial ground consisting of nonperiodic electromagnetic band gap (EBG) structures with adjustable off-center vias is first proposed. According to the projection equivalence, an artificial plane similarly equivalent to a cylindrical metal reflector can be constructed by proper deployment of the vias in the EBG plane, which can strongly focus electromagnetic waves to realize an extremely directive antenna with a high gain. For demonstration, two X -band high-gain differential-fed patch antennas using the proposed EBG planes are accordingly designed. The simulated and measured results indicate high gains of 14.1 and 11.7 dBi are, respectively, achieved for these two antennas, over 1–2 dB improvement than the antennas based on periodic mushroom EBG structures, thus achieving higher aperture efficiencies of 88% and 107.2%; meanwhile, the gain variations are less than 2 dB in the whole frequency band of interest. Compared with a conventional 2 × 2 patch antenna array, the proposed antenna can not only avoid extra feeding network, but also exhibits a higher gain and a higher aperture efficiency within a much wider working band.

High-Isolation Array Antenna Integration for Single-Chip Millimeter-Wave FMCW Radar

By using the second bandgap in mushroom electromagnetic bandgap (EBG) structures, a high isolation can be achieved between transmitting (TX) and receiving (RX) microstrip array antennas integrated with a millimeter-wave single-chip frequency-modulated continuous-wave (FMCW) radar. These EBG structures are much easier to manufacture at millimeter waves as compared to the first bandgap mushroom EBG structures. In addition to improving isolation, the EBG structures are also used to reduce radiation pattern ripples caused by edge diffractions due to surface waves. Experimental validation is performed on antenna level and on the radar system level. For the system-level validation, the antenna arrays have been integrated with a single-chip mm-wave FMCW radar using the bond-wire interconnect technology. Measurement results in the 57–64 GHz band show the TX–RX isolation of 40 dB, which is 15–20 dB better than the isolation between TX and RX arrays without EBG structures. In addition, the radiation pattern ripple caused by edge diffractions is reduced below 3 dB.

Triple band notched mushroom and uniplanar EBG structures based UWB MIMO/Diversity antenna with enhanced wide band isolation

Triple band-rejection MIMO/Diversity UWB antenna characteristics are described in this paper. Proposed antenna discards worldwide interoperability for microwave access WiMAX band from 3.3 to 3.6 GHz, wireless local area network WLAN band from 5 to 6 GHz and X-Band satellite downlink communication band from 7.1 to 7.9 GHz. Mushroom Electromagnetic Band Gap (EBG) structures helps to attain band notches in WiMAX and WLAN bands. Uniplanar plus shaped EBG structure is used for notch in X-band downlink satellite communication band. Decoupling strips and slotted ground plane are employed to develop the isolation among two closely spaced UWB monopoles. The individual monopoles are 90° angularly separated with stepped structure which helps to reduce mutual coupling and also contributes towards impedance matching by increasing current path length. Mutual coupling magnitude of more than 15 dB is found over whole UWB frequency range. The Envelope Correlation Coefficient is less than 0.02 over whole UWB frequency range.The variations in the notched frequency with the variations in mushroom EBG structure parameters are investigated.The antenna has been designed using FR-4 substrate and overall dimensions is (64 × 45 × 1.6) mm3.

Design of band-notched antenna with DG-CEBG

ABSTRACTUltra-wideband (UWB) disc monopole antenna with crescent shaped slot for double band-notched features is presented. Planned antenna discards worldwide interoperability for microwave access (WiMAX) band (3.3–3.6 GHz) and wireless local area network (WLAN) band (5–6 GHz). Defected ground compact electromagnetic band gap (DG-CEBG) designs are used to accomplish band notches in WiMAX and WLAN bands. Defected ground planes are utilised to achieve compactness in electromagnetic band gap (EBG) structures. The proposed WiMAX and WLAN DG-CEBG designs show a compactness of around 46% and 50%, respectively, over mushroom EBG structures. Parametric analyses of DG-CEBG design factors are carried out to control the notched frequencies. Stepwise notch transition from upper to lower frequencies is presented with incremental inductance augmentation. The proposed antenna is made-up on low-cost FR-4 substrate of complete extents as (42 × 50 × 1.6) mm3.Fabricated sample antenna shows excellent consistency in simulated and measured outcomes.

Novel Compact Mushroom-Type EBG Structure for Electromagnetic Coupling Reduction of Microstrip Antenna array

AbstractA novel compact electromagnetic bandgap (EBG) structure consisting of two turns complementary spiral resonator (CSR) and conventional mushroom EBG (CM-EBG) structure is introduced to suppress the mutual coupling in antenna arrays for multiple-input and multiple-output (MIMO) applications. Eigenmode calculation is used to investigate the proposed CSR-loaded mushroom-type EBG (MT-EBG), which proved to exhibit bandgap property and a miniaturization of 48.9% is realized compared with the CM-EBG. By inserting the proposed EBG structure between two E-plane coupled microstrip antennas, a mutual coupling reduction of 8.13 dB has been achieved numerically and experimentally. Moreover, the EBG-loaded antenna has better far-field radiation patterns compared with the reference antenna. Thus, this novel EBG structure with advantages of compactness and high decoupling efficiency opens an avenue to new types of antennas with super performances.

Effect of placing mushroom electromagnetic bandgap structures at the inset feedline of microstrip patches

Placement of mushroom electromagnetic bandgap (EBG) structures at the inset feedline of patch antenna operating at 4.8 GHz is analysed in this study. Proposed design for (i) single patch and (ii) two-element patch array exhibits significant improvement in return loss, bandwidth and mutual coupling loss. Parametric analysis confirms that the optimal position of EBG structures is at a distance of 1.5 mm on both sides of the feedline. It is established that the return loss increases by 8 dB and bandwidth increases by 3.2% for single patch with EBG structures at the feedline. A 6% reduction in antenna size is realised when compared with conventional placing of EBG. Likewise in double patch, placing the EBG structures on either side of the corporate feedline improves the return loss by 2.5 dB and a 12% reduction in size is achieved when compared with customary positioning of EBG. Bandwidth improves by 4.82%. The superior reduction of mutual coupling of double patch with inset edge feed having EBG structures at feedline, in addition to single-column mushroom EBG structures placed between the patches is demonstrated. The mutual coupling loss increases by 3.5 dB and a size reduction of 20% is accomplished. In antenna arrays, EBG structures at the feedline considerably reduce side lobe level and back lobe level and improve directivity, because of optimal radiation patterns. Simulations are validated experimentally.

Power Noise Suppression Using Power-and-Ground Via Pairs in Multilayered Printed Circuit Boards

In this paper, an efficient power noise suppression method using power-and-ground (PG) via pair array in multilayered printed circuit boards (PCBs) is proposed. The power noise suppression performance is doubled by using both power and ground vias compared with the ground via array. The stopband bandwidth of the PG via pair array is derived. The evolvement from mushroom electromagnetic bandgap (EBG) structure to PG via pair array is demonstrated. The proposed method has overcome many shortcomings of the mushroom EBG structures. It is shown that the PG via pair array has excellent power noise suppression, signal integrity (SI), and electromagnetic compatibility (EMC) performance. It is a comprehensive power noise suppression scheme.

Equivalent Circuit Model of an Ultrawideband Hybrid EBG/Ferrite Structure

This letter presents the development of an equivalent circuit model for the previously presented ultrawideband and low-profile hybrid electromagnetic band-gap (EBG)/ferrite structure. It is shown that unlike the equivalent circuit models developed for traditional mushroom EBG structures, the equivalent circuit model for the hybrid structure contains a resistance representing the permeability losses due to the ferrite layer. Additionally, it is shown that both the inductor and resistor equivalent circuit components are frequency dependent and depend on the frequency dependent characteristics of the ferrite.