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In this paper, a compact novel simple design of ultra‐wide bandpass filter with high out of band attenuation is presented. The filter configuration is based on combining an ultra‐wide band composite right/left‐handed (CRLH) band pass filter (BPF) with simple uni‐planar configuration of complementary split ring resonator (UP‐CSRR). By integrating two UP‐CSRR cells, the ultra‐wideband CRLH filter roll‐off and wide stopband attenuation are enhanced. The filter has 3 dB cutoff frequencies at 3.1 GHz and 10.6 GHz with insertion loss equals 0.7 dB in average and minimum and maximum values of 0.48 dB and 1.05 dB, respectively over the filter passband. Within the passband. The transition band attenuation from 3 dB to 20 dB is achieved within the frequency band 1.9 GHz to 3.1 GHz (48%) at lower cutoff and the frequency band 10.6 GHz to 11.4 GHz (7%) at upper stopband. Moreover, the filter has a wide stopband attenuation >20 dB in frequencies 11 GHz to 13.6 GHz (21%) and ends with 3 dB cutoff frequency at 14.8 GHz. Furthermore, the designed filter size is very compact (23 × 12 mm2) whose length is only about 0.17 λg at 6.85 GHz. The filter performance is examined using circuit modeling, full‐wave simulations, and experimental measurements with good matching between all of them. [ABSTRACT FROM AUTHOR]

This article introduces a new design and analysis of a compact reconfigurable bandpass/lowpass filter based on compact negative refractive index metamaterial transmission line. The filter equivalent circuit has been designed as a cascade of three cells of bisected‐Π/Π configuration. The reconfigurable function was achieved using inserted switches in ON and OFF modes within the cells. The filter works as bandpass when all switches are in ON condition and for lowpass switch‐1 is in OFF and switch‐2 in ON condition. The low pass filter has 3‐dB cutoff frequency of 3.25 GHz with a selectivity of 170 dB/GHz. The bandpass filter is cantered at 3.65 GHz and has a well‐matched pass band with insertion loss of 0.2 dB and wide stop band with two transmission zeros (TZs). The frequency positions of TZs are independently varying with series and shunt loading elements. The filter performance has been validated through circuit model, electromagnetic simulation, and experimental measurements. The electrical size of bandpass filter excluding feed line is 0.22 λg × 0.20 λg (12 × 11 mm2) at center frequency of 3.65 GHz and for lowpass filter is 0.19 λg × 0.18 λg at cutoff frequency of 3.25 GHz. The filter can be applied in suitable for different wireless applications. [ABSTRACT FROM AUTHOR]

Fifth‐generation millimeter‐wave devices with multiple antennas require minimal mutual interference for better overall performance. This article presents a simple but novel technique to improve the isolation between closely packed slot antenna arrays. A printed ridge gap waveguide (PRGW) structure is used to realize a low loss millimeter‐wave array's feeding mechanism. By optimally introducing a defective upper plate within the PRGW structure, the measured port isolation of the antenna elements is improved by 17 dB at 61.3 GHz. The antenna array is impedance matched to the feeding PRGW structure over a wide frequency range of 54–67 GHz. Moreover, the radiation patterns are consistent showing broadside radiation before and after introducing the defect in the PRGW structure. The fabricated prototype of the PRGW fed slot antenna array validated the predicted isolation and return‐loss bandwidths of the proposed radiating system. [ABSTRACT FROM AUTHOR]