Low-cost Integrated Phased Array Antennas
Two-Way Ka-Band Phased Array System for Satellite Communication on-the-move (Collaboration with C-COM Satellite Systems):
In recent years, the high potential of the Ka-band satellite communications has led to a huge interest in this range of frequencies for low-cost, low-profile, and high performance land-mobile terminals (Satcom On-The-Move). Meanwhile, phased array systems provide a feasible solution to continuously track the satellite directions in a fast and accurate manner. Hence, implementing two-way Ka-band phased array systems has been the centre of attention in many research programs. One of the important challenges involved in two-way Ka-band phased array system design is to meet the radiation mask requirements forced by satellite communication standards for transmitting mode of land-mobile terminals. C-COM project is a multifaceted research focused on phased array antenna design, fabrication, and measurement for Ka-Band satellite communication applications. It covers various aspects of phased-array systems including 1) antenna array design and analysis, 2) RF/mm-wave circuit design, 3) Ka-band phase shifter design, 4) satellite tracking algorithms, and 5) mechanical structure design.
Design and demonstration of calibration system for ka band phased array antennas
Calibration is an inevitable part of any phased array antenna. It has the capability of minimizing the unwanted effects of errors associated with the limitation in antenna fabrication, element positioning, and non-ideal electrical components. The calibration prototype operates based on single-point measurement in low-IF topology for characterizing phase and amplitude of each phased array element.
In this design, which is known as low-IF topology, two separate sources of RF signals are divided in power and are down converted to generate two different sets of I and Q signals, one as a reference signal and the other as a main signal. This technique is used to correct the quadrature errors and systematic errors effectively. Therefore, phases and amplitudes can be characterized precisely to have an optimized beamforming..
Main aspects of the project:
• Operating frequency of 29.75 GHz.
• Dynamic range of 35dB.
• Phase error of less than 5 degrees and amplitude error of 0.7dB.
• It has the capability of correcting itself through the calibration process.
Substrate Integrated Waveguide (SIW) Integrated RF circuits and antennas for low-cost millimeter-wave applications:
SIW is a periodic guiding structure that allows the integration of traditional metallic Rectangular Waveguide (RWG) in a planar form. It preserves most of the RWG characteristics such as low conduction loss which dominates at millimeter-wave. However, it is low cost and compatible with other fabrication techniques, such as PCB and LTCC technologies. Therefore, the SIW is an excellent candidate for high Q-factor circuits and low loss antenna feeding networks (high radiation efficiency). It minimizes the conduction loss that dominates at millimeter-wave.
Miniaturize Ka-band Phase-shifter for integration with phased-array antennas:
Phase Shifter is considered as the most substantial component of every Phased Array Antenna Systems. Among different solutions in realization of compact phase shifters, analog phase shifters based on tunable materials has played an important role due to their simplicity and compactnes well as their fabrication process. Liquid Crystals (LCs), BSTs and MEMs are the tunable material or devices which have been utilized for this purpose in the literature. Miniaturization of full-range 360-degree phase shifters for Ka-band applications due to implementation of huge number of antenna elements is an essential requirement. These types of phase shifters should be also optimized in terms of; Return Loss, Phase Shift Error, Phase Shift Non-Linearity, Loss variations and Figure of Merit (FoM). The objective of this research is to investigate the characteristics of existing phase shifters and for the following steps, our objective is to find an optimal solution for realization of these kinds of phase shifters.
A low-cost solution for millimeter-wave phased array antenna systems:
Phased-array antenna is turning out to be the only solution for a robust wireless communication at millimeter-wave. Combining both the design challenges of a delicate analog RF circuitry for phased arrays, and the large arrays which occupy a large area to be implemented on the expensive die, we are seeking a solution to find a suitable balance between cost and performance for commercial millimeter-wave applications.
Efficient Phased Array Antenna Systems for Millimeter-wave Applications:
Modern millimeter-wave (mm-wave) radar and communication systems high gain and high efficiency, and wide bandwidth antennas are required to significantly improve the system performance. In order to realize these characteristics, highly efficient array antennas are needed as the frequency increases to mm-wave band as the radiation efficiency of traditional antennas degrade significantly. Substrate Integrated waveguide (SIW) –integrated dielectric antenna array is an excellent candidate due to the absence of conduction loss (high radiation efficiency).
The antenna array specifications are :
• The operating frequency range 35-37 GHz.
• The peak gain is ~ 21.60 dB (measured) the operating frequency bandwidth.
• The radiation efficiency equals 80 % (measured) over the operating frequency bandwidth.