The Vivaldi antenna and its feeding transition is investigated. A tapered transition from microstrip to symmetric double sided slot line, fabricated on a low dielectric constant substrate, exhibits a very wide operating frequency range, with no need for a shorting hole. The parameters of the antenna which influence the constancy of beamwidth with frequency are discussed, and the ability to determine the required beamwidth by controlling the antenna length is shown.

Improved design of the Vivaldi antenna

Endfire tapered slot antennas are suitable for many integrated circuit applications, imaging and phased arrays. We report on an investigation of single elements of such antennas, including slots which are exponentially tapered (Vivaldi), linearly tapered (LTSA) and constant width (CWSA). For antennas of all types, a good general agreement is obtained for curves of beamwidth versus length, normalized to wavelength, when one compares the data with that for traveling-wave antennas published by Zucker. An important condition for this agreement is that the effective dielectric thickness, defined in the text, is in a certain optimum range. This condition is qualitatively explained in terms of the theory for traveling-wave antennas.

Endfire tapered slot antennas on dielectric substrates

A comprehensive review of integrated circuit antennas suitable for millimeter and terahertz applications is presented. A great deal of research was done on integrated circuit antennas in the last decade, and many of the problems associated with electrically thick dielectric substrates, such as substrate modes and poor radiation patterns, have been understood and solved. Several antennas, such as the integrated horn antenna, the dielectric-filled parabola, the Fresnel plate antenna, the dual-slot antenna, and the log-periodic and spiral antennas on extended hemispherical lenses, which have resulted in excellent performance at millimeter-wave frequencies, are covered in detail. A review of the efficiency definitions used with planar antennas is included. >

Millimeter-wave and terahertz integrated circuit antennas

Tapered slot antennas (TSAs) with a number of potential applications as single elements and focal plane arrays are discussed. TSAs are fabricated with photolithographic techniques and integrated in either hybrid or MMIC circuits with receiver or transmitter components. They offer considerably narrower beams than other integrated antenna elements and have high aperture efficiency and packing density as array elements. Both the circuit and radiation properties of TSAs are reviewed. Topics covered include: antenna beamwidth, directivity, and gain of single-element TSAs; their beam shape and the effect of different taper shapes; and the input impedance and the effects of using thick dielectrics. These characteristics are also given for TSA arrays as are the circuit properties of the array elements. Different array structures and their applications are also described. >

The tapered slot antenna-a new integrated element for millimeter-wave applications

The Vivaldi antenna, a form of tapered slot radiator, has been shown to produce good performance over a wide bandwidth, limited only by the traditionally used slotline to microstrip feed transition. The authors present a new antenna, the balanced antipodal Vivaldi, which incorporates an ultrawide bandwidth transition and overcomes the poor polarisation performance of the antipodal form. Good performance over a 1 to 40 frequency range has been obtained. The use of the antenna in a linear phased array has also been investigated using elements constructed on high permittivity substrate. Wideband wide angle scanning with good cross-polarisation levels is obtained.

Balanced antipodal Vivaldi antenna for wide bandwidth phased arrays

The Vivaldi Aerial is a new member of the class of aperiodic continuously scaled antenna structures and, as such, it has theoretically unlimited instantaneous frequency bandwidth. This aerial has significant gain and linear polarisation and can be made to conform to a constant gain vs. frequency performance. One such design has been made with approximately 10 dBI gain and ?20 dB sidelobe level over an instantaneous frequency bandwidth extending from below 2 GHz to above 40 GHz.

The Vivaldi Aerial

The coplanar patch antenna is a recent addition to the range of planar radiators. This paper presents some results for this type of antenna. It has good front to back ratio (15 dB) and low cross polarisation (-20 dB) performances and these have been achieved by exploiting the lens like effects of the high dielectric constant substrate.

A Coplanar Waveguide Antenna for MMICs

A digital instantaneous frequency measuring receiver (DIFM) has been built at Ka-band with a frequency resolution of 25 MHz (9 bit) using a five discriminator binary system digitised to 11.25 degrees. Absolute frequency accuracy is dispersion limited to 100 MHz. A simplified system block diagram is shown in fig. 1. Advanced technology is used in each of the three sections to obtain a compact unit with a performance limit set by the inherent frequency dispersion in the microstrip discriminator circuitry. This paper describes the design. construction and performance of the complete DIFM receiver with special attention given to the CAD techniques based on circuit modelling to allow microwave discriminator design to be carried out under conditions of severe frequency dispersion.

P. J. Gibson

Papers

The Vivaldi Aerial

A Coplanar Waveguide Antenna for MMICs

A 9 Bit DIFM Receiver for Ka-Band