Travelling wave, broadband, and frequency independent antennas. The text explains both the basic theory of antennas and its application to practical designs. This chapter discusses the way by which typical measurements can be understood in terms of classical electromagnetic theory. Frequency independent antennas ieee conference publication. The log periodic antenna gives dual cp over the same bandwidth, needs a simple beamformer. Udaya shankar, ravi subrahmanyan abstractprecision measurements of the spectrum of the cosmic radio background require frequency independent antennas of small electrical dimensions. An octave bandwidth frequency independent dipole antenna. Technical documentation frequently asked questions for 24 ghz industrial radar what is radar. Frequencyindependent antenna article about frequency. Geometrically, frequencyindependent antennas are composed of a multiplic. Frequency independent antennas multimode comparison by kyle andrew zeller antennas with frequency independent properties have previously been developed for applications with various polarization requirements.
Spiral antennas, a type of frequency independent antenna, have been studied for over 40 years. It will also appeal to practicing engineers working on antenna development. Antenna laboratory, electrical engineering research laboratory, engineering experiment station. Frequencyindependent fi antennas are radiating structures capable of maintaining consistent impedance and pattern characteristics over. It consists of metal sheet perforated by holes of uniformly expanding size. Frequency independent antennas 1st edition elsevier. Frequency antenna an overview sciencedirect topics. A second main type of antenna used in gpr systems is the frequencyindependent antenna. We describe the design of a wideband fatdipole antenna with a sinusoidal. Broadband antennas frequency independent bandwidth in the range 40. An octave bandwidth frequency independent dipole antenna agaram raghunathan, n. Pseudo frequency independent antennas the idea of a pseudo frequency independent antenna is illustrated by the horn antenna shown in fig. A survey of the very wide band and frequency independent.
Technical documentation frequently asked questions for 24. Wide band antennas frequency independent bandwidth in octave range. An antenna is called frequency independent if it satisfies two principles. There is a class of antennas whose pattern as well as impedance is practically independent of frequency for all frequencies above a certain value. Wideband antennas can implemented by using self complimentary structures also. Again this bandwidth is at the discretion of the designer. Logperiodic designs based on periodic structure theory. Frequencyindependent fi antennas are radiating structures capable of maintaining consistent impedance and pattern characteristics over multipledecade bandwidths. In theory the process can continue to higher octaves. Multiband antennas antenna resonate at different frequencies. In 1954, rumsey, applying a theory that an antenna specified entirely by angles would have characteristics which are independent of frequency, suggested that. Conical logspiral antennas have been constructed to operate over more than 40 to 1 band wid ths. Frequency independent antennas by rumsey, victor henry.