In this Letter, a quarter cylindrical dielectric resonator antenna (Q-CDRA) with a low profile and circular polarisation (CP) is presented for wideband and multiple-input-multiple-output (MIMO) systems. The approach used to obtain a reduced wideband CP antenna is realised by deforming the geometry of the CDR to a quarter cylinder and using a quasi-spiral feedline to excite two resonant modes in phase quadrature (HEM 11 and HEM 12). The proposed design exhibits a wide-impedance bandwidth (BW) of 34% (4.4-6.2 GHz) with a low measured coupling level<−15 dB, and an axial ratio BW of 24.4% (4.5-5.75 GHz). The antenna gain is stable through the operating BW with a gain peak of 6.4 dBi. In addition, the antenna has a low cross-polarisation in the boresight direction with low envelope correlation coefficient<0.03. The presented design is suitable for RHCP WLAN applications.
This work proposes an implementation of wireless sensor node characterized by its very low power consumption. The node comprises three main components: Xbee module, low power PIC microcontroller and digital sensor. The node can be set to sense then transmit data via one of two transmission methods: periodic and by interruptions. To evaluate the power consumption; currents in the node is measured during the different transmission stages for both methods. As a result, a significant reduction in the power consumption is shown particularly in sleep mode compared to conventional transmission methods. The characteristic of low power consumption makes the proposed node practically ecologic. It can also be fed with the extrem low power supplied by an energy harvesting system.
In this article, a new design of a compact printed rectangular antenna for wireless local area network (WLAN) applications in 802.11a is investigated. The defected ground structure (DGS) technique is successfully used to reduce the ground plane by cutting a large slot to achieve significant miniaturization. The ground plane structure consists of inverted ‘L’ shape. The rectangular radiating element has a size of 6 × 5 mm2 and is connected to a microstrip transmission feed line. The simulated and measured resonance frequency of the single‐band antenna is approximately 5.8 GHz and may cover an impedance bandwidth of 1 GHz for the measurement and 1.65 GHz for the simulation. The simulated and the measured data are in good agreement. The proposed antenna is very compact (10 × 6 mm2) and its impedance bandwidth is suitable for the 5.2‐5.8 GHz WLAN communication systems.
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