Design of Six Element MIMO Antenna with Enhanced Gain for 28/38 GHz mm-Wave 5G Wireless Application

The fifth-generation(5G)wireless technology is the most recent standardization in communication services of interest across the globe.The concept of Multiple-Input-Multiple-Output antenna(MIMO)systems has recently been incorporated to operate at higher frequencies without limitations.This paper addresses,design of a high-gain MIMO antenna that offers a bandwidth of 400 MHz and 2.58 GHz by resonating at 28 and 38 GHz,respectively for 5G millimeter(mm)-wave applications.The proposed design is developed on a RT Duroid 5880 substrate with a single elemental dimension of 9.53×7.85×0.8 mm^(3).The patch antenna is fully grounded and is fed with a 50-ohm stepped impedance microstrip line.It also has an I-shaped slot and two electromagnetically coupled parasitic slotted components.This design is initially constructed as a single-element structure and proceeded to a six-element MIMO antenna configuration with overall dimensions of 50×35×0.8 mm^(3).The simulated prototype is fabricated and measured for analyzing its performance characteristics,along with MIMO antenna diversity performance factors making the proposed antenna suitable for 5G mm-wave and 5G-operated handheld devices.

Triple-Band Circularly Polarized Dielectric Resonator Antenna (DRA) for Wireless Applications

This paper proposes a new dielectric resonator antenna(DRA)design that can generate circularly polarized(CP)triple-band signals.Atripleband CP DRA antenna fed by a probe feed system is achieved with metal strips structure on side of DRA structure.The design start with conventional rectangular DRA with F shaped metal strips on DRA structure alongside the feed.Then,the F metal strip is enhanced by extending the length of the metal strip to obtain wider impedance bandwidth.Further improvement on the antenna performance is observed by improvised the conventional DRA structure.The method of removing part of DRA bottom resulted to higher antenna gain with triple band CP.The primary features of the proposed DRA include wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The primary features of the proposedDRAinclude wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The CP BW values recorded by the proposed antenna were∼11.27%(3.3–3.65 GHz),12.18%(4.17–4.69 GHz),and 1.74%(6.44–6.55 GHz)for impedance-matching BW values of 35.4%(3.3–4.69 GHz),1.74%(5.36–5.44 GHz),and 1.85%(6.41–6.55 GHz)with peak gains of 6.8 dBic,7.6 dBic,and 8.5 dBic,respectively,in the lower,central,and upper bands.The prototype of the proposed antenna geometry was fabricated and measured.A good agreement was noted between the simulated and the measured results.

Stability Analysis and Efficiency Improvement of a Multi-converter System Using Multi-objective Decision Making

Multi-converter system is mainly used in advanced automotive systems.Different converters and inverters are taking part in automotive systems to provide different voltage levels in a multi-converter system.It involves constant voltage load(CVL),constant power load(CPL)and other loads.The CPL in such systems offers negative impedance characteristic and it creates a destabilizing effect on the main converter.The effect of destabilization can be reduced by increasing the CVL or inserting parasitic components.Attempts have been made by authors to improve the stability by using parasitics of different components such as switch,diode and inductor.Influence of insertion of parasitics including the series equivalent resistance of the filter capacitor and variation in CVL on the performance of main converter is mathematically analyzed and conflicting behavior between system stability and efficiency is observed.The optimum solution between these two functions is obtained by using multi-objective decision making(MODM)by varying parasitics of different components and CVL.An attempt has been made to demonstrate the effect of CVL load and the parasitics on the stability and efficiency of the main converter,experimentally.

Computation of Resonant Frequency of Gap-coupled Ring Microstrip Antennas

In this paper, an analytical model for computing the resonant frequency of the gap-coupled ring microstrip patch antennas is developed. The analytical model is based upon the cavity model along with circuit theory. Using the field expressions and boundary conditions, the transcendental equation for the structure is developed. The analytically computed results are compared with the simulated results. The simulation work is carried out by using computer simulation technology(CST) microwave studio simulator.The comparison between simulated and computed results shows good agreement.