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A quad-band pass filter using back-to-back Tri-State Step Impedance Resonator (TSSIR) for Wireless Applications is presented in this article. The achieved passband center frequencies are 2.45 GHz (for WLAN), 3.5 GHz (for WiMAX), 5.4 GHz (for WLAN), and 8.05 GHz (for Satellite Communications). A unique method of simultaneous vertical and diagonal coupling between TSSIR and conventional two-step SIR structures is introduced here to create Transmission Zeros (TZs) in the stop bands of a quad-band filter. The main objective is to produce controllable TZs through shunt capacitive coupling. In the overall filter design, there are a total seven TZs, and the minimum Insertion Losses (ILs) at the mentioned passband center frequencies are found to be -0.4, -0.6, -0.4, and -0.7 dB. The simulation results (using HFSS 13) are in good correlation with the measured prototype (using Arlon AD 250, height 0.76 mm, Dielectric Constant 2.5). [ABSTRACT FROM AUTHOR]

A five port integrated antenna with high isolation for cognitive radio (CR) application was investigated in this study. The design approach involves both the state of operation in terms of ultra-wideband (UWB) and narrowband (NB), where the former is for sensing and the latter is for the sake of communication. The antenna in UWB state comprises an elliptical patch with a narrow cut on the top whereas four simple comb-like patterns are used to perform the task in NB range. In three of the NB antennas, Complementary Split Ring Resonators (CSRR) are used for impedance matching, in contrast to a Double Circular Ring Resonator (DCRR) in another NB antenna. In order to achieve remarkable inter port isolation, two meander lines of same electrical length are introduced between UWB and NB antennas where the first meander line (ML1) is positioned parallel and the second meander line (ML2) is tilted by an angle of 30° with respect to UWB. The potential outcome of the proposed design senses UWB spectrum from 1.9 GHz − 11.77 GHz along with seven communication tasks simultaneously in terms of single and dual band operations with remarkable gain and high isolation of <-22 dB in all ports. [ABSTRACT FROM AUTHOR]

This communication presents a small size, planar, and two-port wideband multiple-input-multiple-output (MIMO) antenna operating from 2.08 GHz to 5.81 GHz with 94.55% fractional bandwidth. It satisfies the bandwidth requirements of multiple wireless applications in both 5G (sub-6 GHz band) and 4G bands namely Bluetooth (2.4 GHz), LTE (2.5 GHz), WLAN (2.4/5.2/5.8 GHz), and WiMAX (3.5/5.5 GHz). An electromagnetic band-gap (EBG) structure is embedded in the ground plane to reduce the resulting mutual coupling between the antenna elements. As a result, more than 18 dB port isolation is obtained over the entire working band. The important MIMO antenna performance parameters such as envelope correlation coefficient (ECC < 0.05), diversity gain (DG > 9.95 dB), and channel capacity loss (CCL < 0.345 bits/s/Hz) are within the acceptable ranges. Measurement is done on the fabricated antenna. A reasonable agreement is observed between the simulated and measured results. [ABSTRACT FROM AUTHOR]

A compact selective ultra-wideband (UWB) bandpass filter primarily based on a multi- mode resonator is presented in this paper. A modified elliptical split-ring resonator (SRR) embedded in a variant of the ring resonator is employed to configure a microstrip UWB triple-notched bandpass filter with improved in-band and out-of-band filter properties. Further, the bent inter-digital coupled lines with apertures at the backside are applied to overall filter size miniaturization apart from contributing tight coupling through the entire structure. The three notches facilitated by the modified elliptic SRR have gained the ability to suppress the wireless local area network (WLAN) (5.48 GHz), C band RADAR (7.68 GHz), X band RADAR (8.82 GHz) interfering signals profoundly within the UWB. Simultaneously, the other filter attributes likely a uniform forward transmission coefficient with minimum attenuation (0.46 dB ~ 1.52 dB), a high skirt factor (0.88), a wide passband (6.52 GHz) with high fractional bandwidth (FBW) (103.16%), broad upper stopband (3.47 GHz), etc. together establish the proposed filter, suitable for practical UWB applications. The uniqueness of this design lies in the exibility to configure the filter as either a double-notched or a triple-notched bandpass filter by altering only the aspect ratios of elliptical SRR. Simulated filter characteristics are compared with the results obtained by measuring the fabricated prototype, and a good accordance between the compared outcomes validates the design pertinence well. [ABSTRACT FROM AUTHOR]