Resonant Slot Antenna
The design of a resonant slot array antenna in a single layer ridge gap waveguide is presented. Linear and planar array configurations are developed. The linear array includes eight series slots in the ridge gap waveguide that is powered by a coaxial transmission line. I was particularly intrigued by his 'Double Delta Skeleton Slot that consists of two tall and narrow inverted delta loops at 90-degrees to each other and fed either in series or parallel at the bottom. Although a robust remote antenna tuner must be used at the feedpoint, the antenna design has a lot of good things going for it.
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Electronic Theses and Dissertations, 2004-2019
Title
Author
Keywords
Wideband, Dual-Polarized, Differential, SIW, Cavity Backed, Slot, Antenna, Double-Resonant, Circular Polarization, Array
Abstract
A new technique for designing wideband dual-polarized cavity-backed slot antennas is presented. The structure is in the form of a double-resonant, dual-polarized slot antenna backed by a shallow substrate integrated cavity with a depth of approximately one tenth the free space wavelength. The presence of the cavity behind the slot enhances the antenna's directivity and reduces the possibility of surface wave propagation in the antenna substrate when the element is used in an array environment. Moreover, the dual-polarized nature of this radiating element may be exploited to synthesize any desired polarization (vertical, horizontal, RHCP, or LHCP). The double-resonant behavior observed in this substrate-integrated cavity-backed slot antenna (SICBSA) is utilized to enhance its bandwidth compared to a typical cavity-backed slot antenna. A prototype of the proposed antenna is fabricated and tested. Measurement results indicate that a bandwidth of 19%, an average gain of 5.3 dB, and a wideband differential isolation of 30 dB can be achieved using this technique. The principles of operation along with the measurement results of the fabricated prototype are presented and discussed in this dissertation. The SICBSA is investigated as a candidate for use as an array element. A uniform two element phased array is demonstrated to locate the main beam from boresight to thirty degrees. The potential effects of mutual coupling and surface wave propagation are considered and analyzed.
Notes
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Graduation Date
Resonant Slot Antenna Receiver
2010
Advisor
Wahid, Parveen
Degree
Doctor of Philosophy (Ph.D.)
College
College of Engineering and Computer Science
Department
Electrical Engineering and Computer Science
Degree Program
Electrical Engineering
Format
Slot Antenna Resonant Frequency Formula
application/pdf
Identifier
CFE0003066
URL
http://purl.fcla.edu/fcla/etd/CFE0003066
Language
English
Release Date
May 2010
Length of Campus-only Access
None
Access Status
Doctoral Dissertation (Open Access)
STARS Citation
Paryani, Rajesh, 'Design Of A Wideband Dual-polarized Cavity Backed Slot Antenna' (2010). Electronic Theses and Dissertations, 2004-2019. 4226.
https://stars.library.ucf.edu/etd/4226
Included in
There Ain’t No Free Lunch
OK. The English is bad but the title says it all. So many hams are looking for that “all band, does everything” HF antenna.
On VHF and UHF the “tuning” of an antenna is far less critical than on HF. The wavelengths at 144 MHz and above provide a naturally wide bandwidth so that you assemble the antenna and, in most cases, it just works. Nearly all transmitting antennas at VHF and above are resonant types.
There are basically only two classes of HF antennas: Resonant and Non-Resonant. Let’s look at resonant antennas first.
Resonant antennas include (but are not limited to) monoband dipoles, monoband and trapped verticals, mono-band and trapped multiband Yagis, and specialized multiband antennas like fan and parallel dipoles. Resonance may be designed into these antennas by the use of traps, linear loading, stubs, or by the natural resonance of the length of the radiator. With these antennas, resonance occurs only in narrow chunks of spectrum.
Non-resonant antennas include (but are not limited to) long-wires, un-trapped multiband verticals, off-center fed dipoles, and other compromise antennas. These antennas typically require a wide-range antenna tuning unit (ATU).
On HF, the wavelengths are long to very long and resonance becomes more critical. A dipole on 80 meters may have a useful SWR bandwidth of only 60 kHz or so. If you want to work 75 phone with an 80 meter CW antenna, you’ll need an ATU (better referred to as a transmatch) to compensate. All resonant HF antennas – ALL OF THEM – used outside their resonant bandwidth require the use of a tuner. If you are looking for an antenna that will cover 160 through 6 and work efficiently… that hasn’t been invented yet.
Non-resonant antennas may be force-fed using ATUs in conjunction with baluns or feedline current chokes. Baluns and chokes will keep RFI out of your shack and allow the tuner to force-feed the non-resonant antenna so that power is radiated instead of being lost in standing waves or impedance losses. For example, 43 foot verticals are 43 feet long to avoid accidental resonance. In other words, they’re designed to be totally non-resonant. Their balun or unun and associated ATU allow them to work across a very wide spectrum. The lower the frequency, however, the poorer the efficiency of these antennas becomes.
Compromise antennas require compromise solutions and support. There ain’t no free lunch!