iii Abstract Ground penetrating radar (GPR) systems are increasingly being used for the detection and location of buried objects within the upper regions of the earth’s surface. The antenna is the most critical component of such a system. This thesis presents a comprehensive study of resistor-loaded planar dipole antennas for GPR applications using both theory and experiments. The theoretical a...

We demonstrate that an antenna can be used to realize a near-field optical probe that combines spatial resolution well below the diffraction limit with transmission efficiency approaching unity. The probe consists of a planar bow-tie antenna with an open-circuited gap at its apex. We present proof-of-principle measurements using microwave radiation and discuss scaling the antenna to the visible...

The characteristics of a bow-tie slot antenna with tapered tuning stubs fed by a coplanar waveguide (CPW) are investigated. The effects of the antenna dimensional parameters are studied through simulation results and design procedure is developed and verified for different frequency bands. The antenna shows wideband characteristics for radar and wireless communication applications. Numerical si...

This article presents a planar silicon integrated subharmonic mixer on top of photonic-crystal (PC) platform. The local oscillator power is injected through 2-D PC slab to resonant cavity that effectively couples the signal bow-tie antenna. same antenna, which printed cavity, contains an antiparallel Schottky diode pair, performs downconversion. proposed design simple, easy-to-integrate, low-co...

Fractal antenna, as name concerns, uses fractal i.e. structure does not change and repeat it when large focus has created upon it. This repetition feature of this antenna provides a great flexibility that it can be designed and can used in different frequencies. These antennas gives a finite area of coverage but the diameter of perimeter becomes infinite. Fractal antenna is used in most of the ...

Radiation from antennas integrated with indium phosphide (InP)-based resonant tunnelling diode (RTD) oscillators is mainly through the substrate because of the effects of the large dielectric constant. Therefore, hemispherical lenses are used to extract the signal from the backside of the substrate. In this study the authors present a broadband bow-tie slot antenna with a tuning stub which is d...

1. INTRODUCTION There is a great demand for broadband antennas used for many applications such as the ultra-wideband (UWB) communications, the EMI measurements and the wideband radars. Considering the transmission and reception of pulse signals, not only broadband characteristics of input impedance and radiation pattern but also the distortionless condition are required. Among many types of bro...