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Radio Location, Radio Navigation, and GPS Systems
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Radio location is concerned with the use of radio waves for position sensing and locating objects. For this purpose, the radio signals can be used in an active or passive mode. In the passive mode, the characteristics of the radio signals received by a particular object situated in the field are used to determine the location. In the active case, the signals generated by an object yield the information about its location.
Waveguide bandpass filter with easily adjustable transmission zeros and 3-dB bandwidth
Published in International Journal of Electronics, 2018
Amit BAGE, Sushrut Das, Lakhindar MURMU, Udayabhaskar Pattapu, Sonika Biswal
Waveguide bandpass filters play an important role in modern communication, radar, radiolocation and radio navigation systems by virtue of their numerous advantages. Due to this, several waveguide bandpass filters have been proposed using complementary split ring resonator (Bage & Das, 2016; Bahrami, Hakkak, & Pirhadi, 2008) and fractal irises (Bage & Das, 2017; Oloumi, Kordzadeh, & Lotfi Neyestanak, 2009), in recent times. The slot-based cavity structure is also be used to design a bandstop filter and bandpass filter (Barrio, Llorent, & Salazar, 2003; Kirilenko & Mospan, 2001a, 2000, 2001b; Paterson & Anderson, 1976; Yatsuk, Nosenko, & Mospan, 2004). However the stopband performances of these filters are poor and therefore these filters are easily affected by out-of-band interfering signals. To reduce out-of-band interference, these filters should have very sharp cut-off skirt frequency response, which can be achieved by introducing a number of TZs on both sides of the passband. As the frequency of the interfering signals may vary case to case, the placement of these TZs should also be flexible and should be independently controlled without affecting the centre frequency and bandwidth. However, the independent control of these TZs is a challenging task.
On the design of novel half T-square strip fractal antenna
Published in International Journal of Electronics, 2021
Ashwini Kumar, Amar Partap Singh Pharwaha
A fractal antenna is a decent answer for the requirements of the modern compact and multifunctional wireless communication systems. Properties of these fractal geometries have been exploited by researchers for size reduction and to achieve multiband behaviour in antennas. Various multiband antennas have been designed using different fractal geometries (A. Kumar & Pharwaha, 2019a)(Goswami et al., 2018)(Puente-Baliarda et al., 1998). A novel method of generating hybrid fractal antenna using the Minkowski and Hilbert curve has been proposed by (Bangi & Sivia, 2018) for wireless applications. It has been demonstrated by Best (2003) that, as the total length of antenna increases into a fixed size the resonant frequency lowers down. Also, the simple and less complex fractal geometries are more effective than complex fractal geometries for lowering down resonant frequency. A pentagon microstrip antenna has been designed by (RamaDevi, 2012) for navigational applications which operate from 4.2 GHz to 4.3 GHz. Global Positioning System (GPS) can be used to help radio navigation and landing at the airport to increase safety and precision, in safety-of-life services. A dual-band antenna using Minkowski fractal has been proposed by (Ashwini Kumar & Pharwaha, 2019b) for maritime radio navigation services. A dual-band Verre de Champagne fractal antenna has been proposed by (Madhav et al., 2018) for LTE and radar altimeter application which operates at 1.8 GHz and 4.3 GHz. A quad-band antenna has been proposed by (Ram et al., 2017) which is suitable to operate for wireless applications such as fixed-mobile, fixed-satellite (Earth to space), radio navigation, radiolocation, meteorological aids, Earth exploration satellite, and space research. It operates at 2.12 GHz, 6.6 GHz, 9.33 GHz, and 13.25 GHz frequencies. A hybrid fractal antenna with multiband characteristics is proposed by (Y. Y. Kumar & Singh, 2015) for ARNS and other wireless applications which has a maximum bandwidth of 0.499 GHz. The use of fractal structures in antenna design has several advantages like miniaturisation, multiband, make antenna frequency independent, better impedance matching and reduced mutual coupling and some limitation as well: numerical limitations, complexity and gain loss. Thus, from the literature, it is perceptible that there is still a huge possibility of the development of the fractal antenna.