In this paper, a dipole antenna is investigated for 5G New Radio portable devices. This antenna adopts the characteristics of multiple mode resonance. Then, by adjusting the spacing between dipole pairs, the antenna has a good impedance match in a wide frequency band. The -10 dB impedance bandwidth of the antenna is 2.31-5.34 GHz (79.2%). In the operation frequency band, the maximum gain and average gain of the antenna are 8.68 dBi and 4.67 dBi, respectively. It can be used in the 5G Sub-6 GHz NR frequency bands n7/n38/n41/n77/n78/n79 and also compatible with WLAN/WiMAX band.
A four-element multiple-input multiple-output (MIMO) antenna based on a modified Complementary Split Ring Resonator (MCSRR) is presented in this paper for dual-band 5G smartphone applications. An inverted L-shaped radiator is used with MCSRR as an open stub in the ground, where MCSRR is responsible for dual operating bands and enhances the impedance matching. The MCSRR as an open stub in the ground plane creates a notch band that minimizes the interference in 5G wireless communication. The four elements of the antenna are placed in such a way that minimum isolation between antenna elements is obtained, 16.5 dB, without any decoupling, whereas more than 20 dB isolation is achieved by using T-shaped decupling. The antenna achieves dual 10 dB bandwidths from 3.40 GHz to 3.625 GHz and from 3.90 GHz to 4.525 GHz. Envelop correlation coefficient (ECC) is extracted from far-field results to analyse the MIMO antenna performance in practical design consideration.
An infrared (IR) pyroelectric detector for applying to the terahertz (THz) waveband that uses diffraction limited focusing of the THz beam on the sensitive area of the detector is studied. The signal to be detected is coupled to the optical window of the detector through a two-wavelength diameter polytetrafluoroethylene spherical particle-lens based on the terajet effect. We have experimentally demonstrated an enhancement of the IR detector sensitivity by 5.6 dB at 0.2 THz without degradation of the noise equivalent power value. The results show that the proposed method could be applied to increase the sensitivity of various commercial IR sensors in the THz range, requiring no modification of the internal structure and may be applied also to acoustics and plasmonics.
The tapered waveguide as a microwave plasma excitation structure is widely used in the industrial field. However, it needs high input microwave power to ignite and sustain plasma because its electric field is not sufficiently focused in the discharge area. In order to solve this problem, this paper proposes a novel microwave plasma source based on a ridged waveguide. The structure of the proposed microwave plasma source is optimized to focus the electric field in the discharge region by electromagnetic calculations before the plasma excitation. Then, the equivalent circuit model is used to analyze the impedance matching characteristics of the novel device after the plasma excitation. In order to validate this device, a microwave plasma system is built to measure the plasma exciting power and sustaining power in both air and argon at atmospheric pressure. The simulation and experiment are carried out in both tapered waveguide and the proposed device. Simulation results show the electric field of the ridged waveguide is 1.9 times of that of the tapered waveguide when the input power is 1500 W. Moreover, in the experiments, the exciting power and sustaining power of the air and argon plasma in the novel device are lower than those of the tapered waveguide at different gas flow rates.
A compact ultra-wideband Multiple-Input-Multiple Output (MIMO) orthogonal microstrip fed linear tapered slot antenna (LTSA) is planned for frequency notched applications. The projected MIMO antenna comprises of two indistinguishable linear tapered slot antennas excited by two orthogonal microstrip feeds. In this paper, double split-ring resonators (DSRRs) are suggested to develop the isolation between two linear tapered slot antenna elements. A quarter wavelength spur line is entrenched on the feeding part of the micro-strip antenna to attain the notch frequency. The L-shaped spur line adds to the notch frequency at 5.5 GHz targeted to dodge interference from 5-6 GHz WLAN band. The planned antenna is fabricated and labelled in terms of impedance and radiation parameter measurements, compliant with that of properties achieved from full wave simulation. The antenna has congruous gain and well-built radiation pattern. Radiation pattern portrayal confirms high gain in the end-fire direction.
This article reports the development and test of a radio-propagation measurement system based on an 8-bit software-defined radio. Tests are performed in an urban area at the frequency of 733 MHz and compared with numerical prediction from the Altair WinProp commercial suite. The system is portable (1.2 kg), low-cost, based on non-proprietary open-source tools and has the capability of tracking the GPS coordinates of the measured points. Frequency limit of the system is bounded by the software-defined radio in use, and the limit of this present case spans 24 MHz to 1700 MHz. The integrated system does not need user intervention after its initial setup can be operated autonomously.