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Miniaturization and size reduction of multiple feed-line microstrip antenna has been investigated and described in this paper. The dimension of proposed antenna reduced using 3 pair of slit while the resonant frequency of 1800 MHz. Based on simulation and optimization result using EM Simulation, the dimension of proposed antenna can reduced until 94.81% compared with conventional multiple feed line microstrip antenna. This result shows that peripheral slit technique succeeded in reducing the dimension of proposed antenna without change the working frequency of antenna.

This paper proposes the design of a circular polarization microstrip antenna (CPMA) which is optimized using array 4×4 element for microwave radio applications. The bandwidth generated from the proposed antenna is 1559 MHz with a frequency range 9862 MHz – 11241 MHz. The simulation results from AWR Microwave Ofiice 2009 shows that the array CPMA has worked at a center frequency of 10700 MHz with a return loss of −26.57 dB, VSWR of 1.098 and axial ratio (AR) 2.031 dB. This shows that the proposed antenna produces a suitable bandwidth requirements for microwave radio communication systems.

Gain enhancement of circular polarization microstrip antenna using the 8x2 element array method is proposed in this paper. The proposed antenna is intended to work in the frequency range 10700 - 11700 MHz for microwave radio communication systems. To get the maximum gain, the proposed antenna is optimized using an array with 8x2 elements. From the simulation results using EM simulation software, the return loss is -24.62 dB, VSWR is 1.125, bandwidth is 1397 MHz at the frequency of 10950 MHz. Optimization with the 8x2 element array method has been successfully in increasing the gain of the antenna up to 50.09% compared to the 4x2 element array design. The proposed antenna can be a candidate to be used for a receiving antenna in a microwave radio communication system.

Wireless communication systems especially radio microwaves communication need a device that functions as a signal transmitter and receiver where the final device for these processes is an antenna. This paper proposes the design of a circular polarization microstrip antenna for microwave radio communication with range frequency of 10750 – 10950 MHz. Circular polarization with axial ratio 3 dB is obtained by using a truncated corner technique, whereas to increase bandwidth an array method with 2 elements is used. The type of substrate used is Arlon LX 217 with e r of 2.2, thickness (h) of 0.587 mm and loss tangent (tan α) 0.0009. From the simulation results of proposed antenna obtained bandwidth impedance with return loss ≤ −10 dB and VSWR ≤ 2 is 1703 MHz with a frequency range 9831 – 11534 MHz. Furthermore, the axial ratio of the proposed antenna is 2.41 dB while gain is 8.12 dB at working frequency of 10850 MHz. From the results obtained it can be concluded that the proposed antenna is suitable for microwave radio communication.

This paper proposes design of parasitic microstrip antenna with multiple feed line for mobile communication applications at working frequency of 1800 MHz. The purpose of adding multiple feed line is to enhanced the bandwidth of the proposed antenna. The multiple feed line used has an impedance of 100 Ohm and is placed on the edge of the patch parasitic microstrip antenna. The optimal bandwidth of the microstrip antenna is obtained by adjusting the dimensions and position of the multiple feed line. From the simulation results obtained return loss of −15.95 dB, VSWR of 1.379 at work of frequency 1800 MHz and bandwidth of 328 MHz with a frequency range 1735 – 2053 MHz or increased 262.13% compared to parasitic microstrip antenna. From the results obtained it can be concluded that the use of multiple feed line succeeded in increasing the performance and bandwidth of the microstrip antenna.

The use of Wireless Sensor Network (WSN) in a variety of fields such as military, logistics and environment monitoring has been growing significantly in the last decade. A WSN comprises nodes with capabilities to sense, process and forward information with preferably low energy consumption to prolong the network life-time. This study investigates the use of Reed Solomon (RS) codes as an error correction code to provide reliability to the data transmission in Rayleigh and Nakagami-m distributed fading channels, and their effects on the energy consumption. Simulation results show that while the energy consumption in a network increases in accordance to the increase of the number of nodes for both fading channels, the required energy is significantly higher to obtain low bit error probability for low number of nodes. When the number of nodes in the network is low, the energy needed by the code capable of a higher level of protection almost matches that needed by the code that provides low protection level. The trade-off between code strength and energy consumption is an important factor to consider when the number of nodes in the network is high.

This paper proposes new design of square microstrip antenna with dual feed line for improving bandwidth and axial ratio at work frequency of 2400 MHz. To obtained circular polarization with axial ratio ≤ 3 dB and enhanced bandwidth of antenna, dual feed line is used to improve performance of conventional microstrip antenna. After the simulation process, dual feed line succeed to improved bandwidth of microstrip antenna 131.9 % compared with microstrip antenna with single feed and provide circular polarization with axial ratio 2.44 dB at working frequency of 2400 MHz. compared to the microstrip antenna with a single feed. This research is very usefull for Wi-Fi application in order to improve the level quality of receiver signal.

Rate Compatible Punctured Convolutional (RCPC) code is a sub-class of convolutional code which allows varied levels of data protection to suit different types of data. RCPC is becoming extensively used in telecommunication systems as it offers bandwidth efficiency and simpler hardware implementation compared to convolutional coding, with comparable performance. RCPC codes are attained by puncturing several of the redundancy bits of convolutional codes. As accurate analysis of the bit error probability for a punctured convolutional encoder using state diagram and transfer function is not a straightforward process, in this paper we use nonpunctured equivalent convolutional code to represent the punctured code. There are numerous puncturing patterns to yield RCPC codes from certain convolutional mother code. Our simulation results in AWGN and Rayleigh fading channels show that the same code rates yielded by different puncturing patterns will result in different code performance. Therefore, puncturing pattern is one of the key considerations in generating an RCPC code as it markedly affects the code performance.

We propose a Vertical Bell Laboratories Layered Space-Time (V-BLAST) MIMO complemented with Rate-Compatible Convolutional (RCPC) codes with Zero Forcing (ZF) and Minimum Mean Squared Error (MMSE)-based detection, as a way to attain high-capacity and highly reliable wireless system. The analytical BER of the system is presented and numerically analyzed. The system performance is analyzed in Nakagami-m fading channel, as it is adaptable to various signal statistics and covers a wide range of fading models. Equivalent convolutional code is used to mitigate the complexity arising in the calculations of the RCPC codes parameters. Results show that the use of highrate code allows for bandwidth efficiency while keeping the performance degradation at a minimum level not exceeding 1 dB. It is also shown that the proposed system is able to yield good performance even at the minimum number of antennas.

A Rate-Compatible Punctured Convolutional (RCPC)-encoded Vertical Bell Laboratories Layered Space-Time (V-BLAST) MIMO system to provide a robust wireless communication link is proposed. The V-BLAST detection is based on Minimum Mean-Squared Error (MMSE) criterion, to alleviate the noise enhancement commonly found in the original V-BLAST scheme based on Zero Forcing criterion. Different code rates and transmit powers are allocated to data streams emitted from the multiple transmit antennas, according to the attenuation levels of the subchannels. This scheme is efficient in terms of transmit power and bandwidth usage, as the data stream entering a destructive subchannel is given low transmit power and high code rate. Simulations show that the proposed system can attain good performance at a reasonably low Eb/No.

An improved MIMO system implementing joint source and channel coding in the form of Rate Compatible Punctured Convolutional Code (RCPC Code) and Unequal Error Protection (UEP) is proposed. To ensure a multiplexing gain, a layered architecture, V-BLAST, is employed. Analytical BER is presented and numerical simulations are done to analyze the system performance. The proposed coding scheme allows for consistently higher error-protection level as the code rate decreases. It is also shown that whilst the lower code rates outperforms the higher ones, in terms of larger free distance and lower BER, the SNR range covered is narrower at decreasing levels of BER. This implies the potential bandwidth efficiency to be gained if the higher code rates are used for lower-priority data bits.