This paper provide a review of the active integrated antenna (AIA) technologies. After a brief introduction on the definition and some historical remarks, the paper concentrates on the research effort on the past decades or so. The AlAs are reviewed in its various functions. First, an oscillator-type AIA is presented, followed by very interesting aspects of coupled oscillator arrays for phase control. Use of an AIA concept for efficient RF front ends is described with examples on high-power amplifier AlAs. Next, a phase-conjugation-based retrodirective array is reviewed. Finally, AIA systems for receiving, transmitting, and duplexing are reviewed.

Active integrated antennas

An electronically reconfigurable reflectarray antenna (RRA) with $10\times10$ elements is presented with a detailed design procedure for an improved beam-scanning performance. The element, designed at Ku band using a simple patch structure with one PIN diode and two substrate layers, can be electronically controlled to generate two states with 180° phase difference and low reflection loss. A reflectarray prototype is fabricated and experimentally studied for proof of principle. The limitations of the small aperture size are analyzed in detail, and synthetic optimizations of both feed location and aperture phase distribution are used to improve the beam-scanning performance of the prototype. Experimental results agree well with the full-wave simulations, and scan beams within ${\pm}{50}^\circ$ range are obtained with a maximum aperture efficiency of 17.9% at 12.5 GHz. Consistent scan beams are obtained from 11.75 to 13.25 GHz. Furthermore, the versatile beam-forming capability of the RRA is also demonstrated by a wide-beam pattern synthesis. A fast beam-switching time ( $12\;\upmu \text{s}$ ) is theoretically analyzed and verified by the measurement.

A 1-Bit $10 \times 10$ Reconfigurable Reflectarray Antenna: Design, Optimization, and Experiment

A dual-frequency reconfigurable reflectarray (RRA) is proposed and verified experimentally. The RRA consists of 1600 electronically controllable elements. By integrating only a single PIN diode, the proposed element is capable to operate at two working frequencies with 1-bit phase resolution. The dual-frequency mechanism is explained through the mode analysis, and a parametric study is performed to provide guidelines for determining the two working frequencies. As an example, a 1600-element RRA prototype is realized by assembling five identical $8 \times 40$ subarrays. An field programmable gate array control board is used to achieve real-time phase control of each element individually. The experimental results show that the broadside gains of the RRA are 29.3 and 30.8 dBi at 11.1 and 14.3 GHz, respectively. Excellent beam scanning performance is also obtained at both frequencies.

A 1600-Element Dual-Frequency Electronically Reconfigurable Reflectarray at X/Ku-Band

An optically controlled microwave antenna that reduces the optical power consumed by the antenna and to enable polarimetric detection an optically controlled microwave antenna comprises an antenna array and a feed for illuminating said antenna array with and/or receiving microwave radiation. The antenna array comprises a plurality of antenna elements each including a waveguide, two optically controllable semiconductor elements arranged within the waveguide in front of the light transmissive portion of the second end portion, a controllable light source arranged at or close to the light transmissive portion of the second end portion for projecting a controlled light beam onto said semiconductor element for controlling its material properties, and a septum arranged within the waveguide in front of the light transmissive portion of the second end portion and separating said waveguide into two waveguide portions.

Dual-polarized optically controlled microwave antenna

A detailed overview of various design methodologies and enabling technologies for beam-scanning reflectarray antennas is presented in this article. Numerous advantages of reflectarrays over reflectors and phased arrays are delineated, and representative beam-scanning reflectarray antenna designs are reviewed. For limited field-of-view beam-scanning systems, utilizing the reflector nature of the reflectarray antenna and the feed-tuning technique can provide a simple solution with good performance. On the other hand, for applications where wideangle scan coverage is required, utilizing the array nature of the reflectarray and the aperture phase-tuning approach are the more suitable choices. There are various enabling technologies available for both design methodologies, making them a suitable choice for the new generation of high-speed, high-gain beam-scanning antennas.

Beam-Scanning Reflectarray Antennas: A technical overview and state of the art.

The results of an experimental study, in which time-domain pulses are used to measure the far-field characteristics of an antenna, are presented. Pulses with duration and rise time of the order of 50 ps are generated, in order to characterize the complete frequency (1-18 GHz) behavior of an antenna. An X-band standard-gain horn has been used to verify the overall performance of the measurement system. Excellent agreement between the time-domain and the frequency-domain measurements has been observed. This paper describes the antenna time-domain measurement (ATDM) technique, time-domain gating, the error sources, and the advantages and the disadvantages of such a measurement technique.

Antenna time-domain measurement techniques

A simple and efficient method for determining the complex permittivity of dielectric materials from both reflected and transmitted signals is presented. It is also novel because the technique is implemented using two pyramidal horns without any focusing mechanisms. The dielectric constant of a noninteractive and distributive (NID) mixture of dielectrics is also determined. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 117–119, 2000.

/pdf/a-simple-free-space-method-for-measuring-the-complex-2tdulbydbh.pdf

A Simple Free-Space Method for Measuring the Complex Permittivity of Single and Compound Dielectric Materials

The proposed antenna is a Fresnel-zone-plate antenna (FZPA) in the Ka band that scans the beam of millimeter wave source. The antenna includes a semiconductor wafer (silicon, gallium arsenide) in which a spatially varying density of charge carriers is selectively established through selective optical illumination using a pulse laser. It is shown that the beam of the antenna can be scanned through the space by reconfiguring the masking of the wafer. The beam scanning is done in the transmission mode. The analysis of the far-zone radiation characteristics is presented using physical optics. Results for the antenna gain, the efficiency, and the co- and cross-polar patterns are given.

/pdf/electromagnetic-analysis-of-beam-scanning-antenna-at-5b2qreqtwc.pdf

Electromagnetic analysis of beam-scanning antenna at millimeter-wave band based on photoconductivity using Fresnel-zone-plate technique

Dielectric properties of polyaniline at different frequencies were studied. Cavity perturbation technique was employed for the study. Poly aniline in the powder and pelletised forms were prepared under different environmental conditions. Different samples of poly aniline exhibit high conductivity. However, the conductivity of samples prepared under different environmental conditions is found to vary. All the samples in the powder form have high conductivity irrespective of the method of preparation. The high conductivity at microwave frequency makes it possible to be used for developing microwave components like filters.

https://dyuthi.cusat.ac.in/xmlui/bitstream/handle/purl/2978/Dyuthi-P00413.pdf;sequence=1

Complex permittivity and conductivity of poly aniline at microwave frequencies

In this paper, the design concept of an active reconfigurable reflectarray antenna has been proposed and tested. The elementary radiators are hollow patch antennas loaded with varactor-diode device which its reflected phase can be varied. This phase alteration is based on the variation of the diode capacitance which can be achieved by varying the biasing voltage of the active varactor device. By activating these varactor devices, the phase of each antenna element in the array configuration can be adopted dynamically and consequently its radiation beam can be reconfigured. The advantage above the MEMS switches is complexity of the integration and continues beam scanning capability. The reflectarray incorporating active elements has been built and tested at 6.0GHz. The performance of the proposed active antenna is excellent which pioneers design of arbitrarily reconfigurable antennas.

M. Hajian

Papers

Antenna time-domain measurement techniques

A Simple Free-Space Method for Measuring the Complex Permittivity of Single and Compound Dielectric Materials

Electromagnetic analysis of beam-scanning antenna at millimeter-wave band based on photoconductivity using Fresnel-zone-plate technique

Complex permittivity and conductivity of poly aniline at microwave frequencies

Active scan-beam reflectarray antenna loaded with tunable capacitor