Design of a high gain & ultra wideband microstrip array antenna for avalanche radar

This paper presents the design and construction of a microstrip array antenna operating at 5.3 GHz, to be used as an avalanche sensor in avalanche measurement. The advantage of the antenna is it can achieve a high gain of 15.6 dB with bandwidth of 90%. This was achieved by separating the feed network from the main patches; and increasing the antenna height by installing the feed layer at the back of the patch layer, sharing the same ground plane. In order to ensure the power is transferred smoothly from the main input port, the feed is design in novel spider like tapered feed network while ensuring the overall antenna function is not compromised. © 2011 IEEE

A survey of component carrier selection algorithms for carrier aggregation in long term evolution-advanced

Given that the demand for real-time multimedia contents that require significantly high data rate are getting of high popularity, a new mobile cellular technology known as Long term Evolution-Advanced (LTE-A) was standardized. The LTE-A is envisaged to support high peak data rate by aggregating more than one contiguous or non-contiguous Component Carriers (CCs) of the same or different frequency bandwidths. This paper provides a survey on the case where the LTE-A is working in backward compatible mode as well as when the system contains only LTE-A users. Note that the backward compatible mode indicates that the LTE-A contains a mixture of the legacy Long Term Evolution Release 8 (LTE) users that support packets (re)transmission on a single CC and the LTE-A users that are capable of utilizes more than one CCs for packets (re)transmission. It can be concluded from the study that the CC selection algorithms for newly-arrived LTE users can benefit from the channel diversity and the load status whereas the carrier aggregation that does not allocate all of the available CCs to the newly arrived LTE-A users shown to be more efficient

Prediction of rain-induced cross polarization at millimeter wave bands in guinea

Microwave communication systems are planned to utilize orthogonal polarization. Two independent information channels of the same frequency band sent over a single link to make an optimum use of the frequency spectrum. However, above 10 GHz, the amount of rain aloft can severely degrade the performance of both satellite and terrestrial links, especially in tropical regions, at millimetre wave bands. This paper evaluates the differential attenuation and differential phase shift for the prediction of cross polarization discrimination using a 10-year rain data recorded in Conakry, Guinea. The drop size distribution (DSD) was computed using Marshall and Palmer (MP) model

Simulation of packet scheduling in cognitive long term evolution-advanced

Real Time (RT) and Non-Real Time (NRT) multimedia content demand on mobile devices are increasing at a high pace. Long Term Evolution-Advanced (LTE-A) is expected to cater these demands. However, LTE-A operates at fixed spectrum which leads to spectrum scarcity. Cognitive Radio (CR) is one the promising technologies that is used to overcome spectrum scarcity and implementation of CR into LTE-A will improve spectrum availability and efficiency of the network. Furthermore, with addition of Packet Scheduling (PS) in the cognitive LTE-A, QoS requirement of the mobile users can be guaranteed. However, the study on the stated is very limited. Thus, this paper models, simulates and evaluates performance of five well-known PS algorithms for supporting the RT and NRT multimedia contents. The simulation results show that Maximum- Largest Weighted Delay First (M-LWDF) is the best candidate for implementation in the cognitive LTE-A

A compact and lightweight microstrip antenna array with Wilkinson power divider for X-band application at 9.5 GHz

In this paper, a two-element microstrip antenna array with a compatible 1:2 Wilkinson Power Divider operating at 9.5 GHz for X-band application is presented. The design, simulation and optimization of this work are performed using Computer Simulation Technology (CST) Microwave Studio. The proposed design is shown to exhibit good simulation performances with return loss of -38.21 dB, bandwidth of 493 MHz, and gain of 7.08 dB. Coupled with the antenna array, a 1:2 Wilkinson Power Divider is then designed, simulated and optimized. The simulation result of the power divider exhibits three modes of resonance at 8.0-8.5 GHz, 9.09-10.28 GHz and 11.2-11.5 GHz. The operating frequency at 9.5 GHz resulted an equal power division with insertion loss less than 3.68 dB and less mutual coupling as the isolation factor is at 16.23 dB. The antenna array and Wilkinson Power Divider configuration produced an overall dimension of 83.14 mm 67.34 mm, which realized a portable solution for the parabolic reflector antenna

Design and comparison of printed antennas using meander line technique

The interest for compact antennas in wireless communication increase due to the portability and mobility of the communication devices. Generally, an antenna at low frequency exhibits in large physical size. This project investigates the design of an antenna at 400 MHz. The simulation of the antenna has been performed using CST MWS. Since medical applications are dealing with low frequency, it will lead to large size of antenna which brings a challenge for wireless personal area network (WPAN). It is well known that the antenna performance decreases (according to Chu’s equation) as the size of antenna decreases. Therefore, antenna miniaturization using Meander Line (ML) will be taking place to overcome the challenges. Thus, this paper presents a comparison between i) printed dipole antenna without meander line technique, ii) printed dipole with meander line technique and iii) printed monopole antenna with meander line technique. The results show that an estimation of reduction size by 50% can be achieved using Meander Line technique

Fade margin estimation technique using radar data for satellite link

The fade margin is an important parameter used by the operator to measure the link availability for a given time. Fade margin is a parameter that is used in the design of satellite links to ensure optimal performance of the link. A new technique is proposed where the fade margin of a satellite link can be estimated using attenuation statistics of radar data. Data set acquired from Malaysian meteorological radar for the year 2009 is used in the study. Radar return or reflectivity is used in the process of generating the attenuation values. The reflectivity is first converted into rainfall rate value and the specific attenuation is then calculated. The rain attenuation values can be derived by the multiplication of the specific attenuation and the path length affected. The rainfall rate derived from radar information is used in calculating the slant path attenuation of the satellite link. The databases of rain attenuation is then compiled with the time duration to acquire the cumulative distribution function (CDF) for the specified link. The satellite link investigated are based on the RazakSAT link in relation to its ground station located at Sg Lang, Banting, Selangor, Malaysia for X-band and MEASAT-3 satellite in relation to its ground station at Cyberjaya, Selangor, Malaysia for Ku-band

Design of narrowband tunable filter for LTE Band 5

The objective of this project is to design and develop a tunable bandpass filter for LTE Band 5 that work within the frequency range of 869 MHZ - 894 MHz. The filter characteristic that being tuned in this design is the center frequency while the bandwidth remains the same. The tunability of the design is electronically controlled by adjusting the capacitance value in the filter network. The design is being constrict by the currently available lumped element component in the market. The design methodology of the tunable filter are being introduced in this project. Several thesis and article regarding RF microwave filter design are reviewed before coming up with the methodology for the design

Performance evaluation of multi-interfaced fast handoff scheme for PNEMO Environment

Mobility management is classified into two parts such as location management and handoff management. The earlier one concentrates on location update whereas the later one manages continuous Internet connectivity while the Mobile Router (MR) changes its single point of attachment to the network. Therefore, frequent movement of the MR is one of the significant characteristics in Network Mobility (NEMO) environment. Because, in accordance with the standard Network Mobility Basic Support Protocol (NEMO BSP), the MR utilizes single Interface to attach to the access link. MR requires changing its Care of Address (CoA) when it moves among different wireless access networks. As a result, it can directly influence the performance of the mobility management protocols during inter technology handoff of multi-interfaced MR. This paper proposed a multi-interfaced fast handoff scheme in Proxy NEMO (PNEMO) environment. After that, it represents a comparative analysis between the proposed multiinterfaced scheme, NEMO BSP and the PNEMO scheme respectively. The performance disparities of these schemes are estimated and analyzed via both numerical and simulation approaches. The simulation is performed through NS-3 network simulator. The performance metrics estimated for evaluation are mainly handoff delay and packet loss. It has been perceived that, the proposed scheme performs better compared to the PNEMO scheme and NEMO BSP