Ubaid Ullah

Antenna in LTCC Technologies: A Review and the Current State of the Art

This paper presents a chronological review of the research carried out on antennas in low-temperature cofired ceramics (LTCC) technology over the last ten years or so. Major breakthroughs in LTCC technologies and its shortcomings are highlighted. The current state of the art of LTCC-technology-based antennas is then evaluated. All realizable features of the LTCC-based antennas, which are compact and of light weight and offer high-speed functionality for portable electronic devices, are illustrated. Different techniques used by researchers for broadbanding, multiband designs, and fabrication of LTCC-based antennas are also presented. This paper ends with some recommendations and concluding remarks.

A review of wideband circularly polarized dielectric resonator antennas

This article presents a technical review of circularly polarized (CP) dielectric resonator antennas (DRA) for wideband applications. The primary objective of this review is, to highlight the techniques used by different researchers for generating circular polarization in DRA. First, a general idea of circular polarization and it advantages over linear polarization is presented, and then all the major developments made in the CP DRA are highlighted. The emphasis of the paper is on the wideband circularly polarized dielectric resonator antenna. The current state of the art and all the realizable features of the CP DRA are addressed comprehensively. Finally, some recommendations for future CP DRAs are given and the paper ends with concluding remarks.

Dual-segment corporate feed four elements array antenna for broadband application

A dual-segment four elements corporate feed array antenna operates at the center frequency of 5.55 GHz is designed and analyzed. Each resonator of the antenna is composed of two different dialectic materials stacked together. The aim of dual-segments is to get strong coupling with lower segment of high permittivity and wide impedance bandwidth with upper segment of lower permittivity. Quarter wave (λ/4) transformer is used to design corporate feed line with equally distributed power in each arm. With this setup a 10 dB return loss impedance bandwidth up to 19% (5 GHz-6.1 GHz) is achieved.Simulation of the four elements array antenna is performed using Computer Simulation Technology (CST 2010) and fabricated on Roger RO4003 substrate with εs= 3.38. A good agreement between simulation and measurements results is achieved.

Feed Coupling Comparative Assessment of Selected Microstrip Patch Antenna

Feed coupling comparative assessment of some selected patch antennas is presented. Different available feed configurations were implemented ranging from the conventional microstrip feed line to coaxial feed probe, quarter wavelength feed, inset coupled, and a few available capacitively loaded coupled feed which are also optimized for maximal excitation, and hence, efficiency. Experimental results were understudy and a thorough comparative assessment summary table is presented. It was noted that the inset feed looks more promising.

Bi-polarized Dual-segment Rectangular Dielectric Resonator Antenna

Abstract Theoretical and experimental study on Dual-Segment Rectangular Dielectric Resonator Antenna excited in higher order modes is presented. Previous researchers have only considered fundamental TE111 mode with linear polarization. In this study, fundamental TE111 and higher order TE113 modes are investigated. Furthermore, the effect of an optimized Parasitic Patch (PP) attached on a wall of DRA is studied in terms of antenna polarization, i.e., Linear polarization (LP) and Circular polarization (CP) and modes of propagation. It was found that simulated and measured impedance bandwidth (|S111| ≤10 dB) of the antenna without PP is 42% and antenna with PP is 50%, respectively. The 8% increase in the operating bandwidth of the antenna is achieved by adding PP to DRA which excites degenerate mode, changes polarization of the antenna, and enhances the level of TE113 mode. The results show that TE 111, and TE113 together can be used to design a broadband antenna with both LP and CP. Furthermore, maximum measured gain of 6.2 dB is achieved for the single element configuration without PP at approximately 7 GHz.

Design and analysis of Dual segments two element array antenna for wideband applications

A Broadband Dual-segment two element array mount up with reflector, operates at center frequency of 7.5 GHz is reported. Each Dielectric Resonator (DR) comprises of two DRs with diverse permittivities stacked in concert. The bottom segment is of Barium Zinc Tantalum (BZT) with reasonably high dielectric constant and serves as impedance transformer; while the top segment is of RogersRT6010 of low permittivity and serves as resonator. These DRs are excited by executing T-Junction equal power divider (50Ω – 100 Ω). This arrangement reveals a wide impedance bandwidth of 21% for simulation while 24% for measured. Also a realistic enhance of 2 – 2.5 dB in the gain and directivity of the antenna has been witnessed by optimizing reflector size and location in the near field region of antenna. Analysis of the antenna is performed by implying CST 2008 and fabricated on Rogers 4003C with εs= 3.38. Reasonable agreement between simulated and experimental results was observed.

A novel multi-band dual-segment rectangular Dielectric Resonator Antenna

Modern wireless communication devices demands for multiband operation using single antenna to reduce complexity of the system. In this work a multi-band rectangular shaped Dielectric Resonator Antenna (DRA) is designed and analyzed. A two segments rectangular dielectric resonator with different permittivitys are stacked together, and a notch is created in the top segment of the resonator. By optimizing notch value and position of rectangular Dielectric Resonator (DR) over the microstrip feed line multi-band operation of the antenna is achieved. Parametric study of the antenna is done so as to achieve optimum performance of the antenna in both operating bands. The lower operating frequency band of the antenna gives approximately 14 % (5.3 GHz to 6.1 GHz) impedance bandwidth, whereas upper operating frequency band of the antenna yields almost 8 % (7.2 GHz to 7.8 GHz) impedance bandwidth. Simulation of the proposed antenna is performed using Computer Simulation Technology (CST 2014). Return loss of the antenna is measured using Agilent Technology PNA N5245A network analyzer. A close agreement between simulation and measured results is obtained.

Study on the Effect of Dielectric Structure to the Cylindrical Dielectric Resonator Antenna (DRA)

This paper presents the effect of variation of diameter and height of DR to the resonant frequency and radiation pattern of DRA. Analysis was carried out on the DR with diameter of 10.66 mm and height of 4.4 mm. The simulated and measured resonant frequencies were 3.67 and 3.77 GHz, respectively. The E-plane radiation pattern of CDRA was bi-directional pattern. The analysis was based on the CST simulation which varied the thickness and height of DR with the same increment and decrement of 1 mm. The resonant frequency of CDRA shifts significantly when the height of DR is varied, in contrast to the variation of DR’s diameter. The radiation pattern of antenna does not change when the dimension (height or diameter) of DR were altered.