Mohd Haizal Jamaluddin

An MIMO Rectangular Dielectric Resonator Antenna for 4G Applications

A multiple-input-multiple-output (MIMO) rectangular dielectric resonator antenna (RDRA) for 2.6-GHz Long Term Evolution (LTE) applications is investigated and presented. Two orthogonal modes of the RDRA are excited by using two different feed mechanisms: coplanar waveguide (CPW) and coaxial probe. The measured impedance bandwidth for port 1 and port 2 is 47% (2.09-3.38 GHz) and 25% (2.40-3.09 GHz), respectively. The measured correlation coefficient is 0.03 with nearly 10 dB diversity gain at frequency 2.6 GHz. The MIMO RDRA gives isolation of above 20 dB over the operating frequency. The gain of 4.97 dBi is obtained for port 1 and 4.51 dBi for port 2 at 2.6 GHz. The S-parameters, isolation, gain, correlation coefficient, and diversity gain of the MIMO RDRA are studied, and reasonable agreement between the measured and simulated results is observed .

Omnidirectional Circularly Polarized Dielectric Resonator Antenna for 5.2-GHz WLAN Applications

The rectangular dielectric resonator antenna (RDRA) is presented to generate linearly polarized (LP) with omnidirectional radiation patterns. The proposed omnidirectional LP DRA is fed centrally by a coaxial probe and offers an impedance bandwidth of 130 MHz between 5.15 and 5.35 GHz for dB, which can be useful for 5.2-GHz WLAN applications. It is noted that by introducing several inclined slits to the diagonal and sidewalls of the RDR and also deducting a rectangular part of the top wall of the LP RDRA, degeneracy mode is excited to generate the circularly polarized (CP) fields. The proposed omnidirectional CP DRA with axial-ratio (AR) bandwidth of 210 MHz was designed for WLAN (5.15-5.35 GHz) applications. A parametric study is presented. The proposed CP DRA is built, and the characteristics of the antenna are measured. Very good agreement between numerical and measured results is obtained.

Novel Design of Compact UWB Dielectric Resonator Antenna With Dual-Band-Rejection Characteristics for WiMAX/WLAN Bands

A novel compact dual band-notched dielectric resonator antenna (DRA) for ultrawideband (UWB) applications is proposed. Here, the bandwidth enhancement and the first band notch is realized by embedding a stub that is located to the hollow center of a U-shaped feedline simultaneously. By etching an inverted T-shaped parasitic strip at the back plane of an antenna that is surrounded by a dielectric resonator (DR), the second band rejection is created. By cutting a slot at the proper position on the ground plane, the width of the second band notch is controlled. The proposed antenna size is 12 ×30 ×6 mm3 or about 0.124 λ×0.31 λ×0.062 λ at 3.1 GHz. The measurement results demonstrate that the proposed DRA provides acceptable radiation performances such as an ultra-wide impedance bandwidth of around 122% with two sufficient band rejections in the frequency bands of 3.22-4.06 and 4.84-5.96 GHz, high radiation efficiency, and nearly constant gain.

Microstrip dipole antenna analysis with different width and length at 2.4 GHz

This paper discusses the design and simulation of microstrip dipole antenna at 2.4 GHz. In this antenna design, Agilents Advanced Design System (ADS) software using momentum simulation is employed to analyze the entire structure. Different width (W = 3, 5, 7, 9 mm) of the arm of dipole antenna is analyzed to study on the performance of frequency resonance. From the simulation, the wider the width will lower the resonance frequency of the antenna. Different width makes the frequency resonance of the antenna shifting lower or higher than 2.4 GHz. In this case, the length (L) of the dipole arm needs changes. Optimization value of the length is needed to make the frequency resonance at 2.4 GHz. The simulation result gives the bandwidth achieved of this microstrip dipole antenna is between 11 and 13 %. Three different width of dipole antenna have been fabricated and presented here in this paper. The properties of antenna such as input return loss and bandwidth have been investigated and compared between simulations

A Novel Square Dielectric Resonator Antenna With Two Unequal Inclined Slits for Wideband Circular Polarization

A novel dielectric resonator antenna (DRA) is presented for wideband circular polarization (CP). Two unequal inclined slits are loaded on the diagonal of the square DR to excite a CP mode. The effect of variation of ratio between the length of the slits on the CP and impedance characteristics is studied. The DR is excited by a proper tapered strip, connected to the input microstrip line from one side, and finally matched by a chip resistor from the lateral side. As the key parameters, the position of the excitation and matching lines and the impedance of the chip resistor are carefully optimized to adjust and improve the CP. The proposed configuration offers a relatively compact and easy-to-fabricate feeding network and multiresonant performance providing a 3-dB axial-ratio and impedance bandwidth of about (43-50)% around 3.7 GHz, gain between 4 and 6 dBi. The CP and impedance parameters of the antenna are studied, and reasonable agreement between the measured and simulated results is observed.

Microstrip Patch Antenna Array at 5.8 GHz for Point to Point Communication

This paper described the design of microstrip patch array antenna with operating frequency at 5.8GHz for point to point communication. The array of four microstrip rectangular patch antennas with inset feed based on quarter-wave impedance matching technique were designed, simulated, fabricated and measured with the aid of microwave office software. The simulation and measurement result met the IEEE 802.11a standard and able to operate in upper UNII band for point to point communication. The 4times4 array has a return loss of -30.42 dB with 15% bandwidth. The gain obtained from simulation is 16 dB with 9deg half power beamwidth (HPBW)

Mutual Coupling Analysis Using FDTD for Dielectric Resonator Antenna Reflectarray Radiation Prediction

A simulation technique based on Finite-Difierence Time- Domain (FDTD) is used to analyze mutual coupling efiects in re∞ectarray environment. The neighbouring element method has the ability to analyze actual non-identical re∞ectarray unit-cell accurately compared to the traditional Floquet simulation which assumes all unit- cell is identical. It is also found that the nearest neighbouring unit-cell located in E-plane has a larger mutual coupling efiects compared to the neighbouring unit-cell in H-plane. A good agreement is shown between simulation and measurement results. This technique presents a new prediction method for the radiation pattern of re∞ectarray antenna.

Microstrip dipole antenna for WLAN application

This paper describes numerical simulation, fabrication and experimental measurement of microstrip dipole antenna at 2.4 GHz for WLAN application. In this antenna design, Agilents ADS software using momentum simulation is employed to analyze the entire structure. The properties of antenna such as bandwidth, radiation pattern and half power beamwidth have been investigated and compared between simulation and measurements. The cross-polar isolation of the microstrip dipole antenna is in the range of 3 to 17.32 dB. The typical half power beamwidth (HPBW) of the microstrip dipole is 60° for E plane and 75° for H plane. Performance comparison between dipole and monopole antenna is also made in term of bandwidth and Input return loss.

Single-Phase Wireless LAN Based Multi-floor Indoor Location Determination System

Current indoor location determination systems require an offline training phase in order to build a radio map that contains a list of radio fingerprints at known locations. The process of building this radio map is usually a time-consuming and requires an intensive work where the accuracy of these systems depends on various factors such as the number of collected radio fingerprints and the time in which they were collected. This paper presents an indoor location determination system that does not require a time-consuming offline training phase in order to build the radio map. Instead, the system uses the online phase for both reading the current Received Signal Strength (RSS) and inferring the location values for each random variable using Bayesian Graphical Model (BGM). The proposed system is based on Markov Chain Monte Carlo (MCMC) sampling techniques in order to draw samples from the posterior distribution. We will also introduce the Feed and Infer algorithm to be used in conjunction with the proposed graphical model. The proposed system will be compared with other single-phase systems.

Rectangular Dielectric Resonator Antenna Array for 28 GHz Applications

In this paper, a Rectangular Dielectric Resonator Antenna (RDRA) with a modified feeding line is designed and investigated at 28 GHz. The modified feed line is designed to excite the DR with relative permittivity of 10 which contributes to a wide bandwidth operation. The proposed single RDRA has been fabricated and mounted on a RT/Duroid 5880 (er = 2.2 and tanδ = 0.0009) substrate. The optimized single element has been applied to array structure to improve the gain and achieve the required gain performance. The radiation pattern, impedance bandwidth and gain are simulated and measured accordingly. The number of elements and element spacing are studied for an optimum performance. The proposed antenna obtains a reflection coefficient response from 27.0 GHz to 29.1 GHz which cover the desired frequency band. This makes the proposed antenna achieve 2.1 GHz impedance bandwidth and gain of 12.1 dB. Thus, it has potential for millimeter wave and 5G applications.