Mateo Burgos-Garcia

FOUR-OCTAVE SIX-PORT RECEIVER AND ITS CALIBRATION FOR BROADBAND COMMUNICATIONS AND SOFTWARE DEFINED RADIOS

This paper presents a software defined radio six-port receiver for a novel broadband mobile communications system. The prototype covers the frequency range from 0.3 GHz to 6 GHz, and operates with up to 100 MHz-wide channels. The multi-band and multi-mode demodulation capabilities of the six-port architecture have been experimentally demonstrated. The six-port receiver has been satisfactorily proved for high data rates (up to 93.75Mb/s, limited by the available test instruments). An efficient six-port autocalibration method suitable for large instantaneous bandwidth systems is presented and validated.

SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell

This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad Politécnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar.

Direct Baseband I-Q Regeneration Method for Five-Port Receivers Improving DC-Offset and Second-Order Intermodulation Distortion Rejection

Six-/five-port architecture has advantages compared with conventional receiver architectures, especially for high frequencies and high-data-rate applications. However, it requires two/one additional baseband outputs and a calibration process to recover the original signal. While this problem is resolved in conventional six-port configurations, a solution is needed for five-port architectures. We propose an I/Q regeneration method based on the use of a simple analog circuit, eliminating one baseband output. The structure of this circuit derives from a mathematical formulation, which is presented in this paper. The validity of the method has been experimentally proved in a five-port receiver prototype. In addition, its capacity to reduce the dc-offset and second-order intermodulation distortion has been demonstrated.

Through-the-Wall Surveillance With Millimeter-Wave LFMCW Radars

The use of millimeter-wave radars allows a weight and size reduction of circuits and antennas, which is an important characteristic for Through-the-Wall Surveillance (TWS) applications. Furthermore, when using the millimeter-wave band, a large amount of bandwidth can be easily transmitted, given that the relative bandwidth is smaller. This leads to a high range resolution that allows for the discrimination of several targets that are very close in range, e.g., inside a room. The azimuth resolution is also improved due to the availability in this band of directive antennas with small dimensions. This paper studies the feasibility of using a millimeter-wave linear frequency-modulated continuous-wave radar in a TWS application. A TWS experiment in a real scenario has been done to demonstrate the validity of the theoretical analysis.

Portable High Resolution LFM-CW Radar Sensor in Millimeter-Wave Band

This paper presents a portable radar sensor developed in the Universidad Politecnica de Madrid. The system transmits a Linear Frequency Modulated Continuous Wave (LFM-CW) with two-antenna configuration for transmission and reception. The radar transmits at millimeter-wave band with a maximum bandwidth of 2 GHz and a transmitted power of 1 W. The system is modular, compact and lightweight. The sensor allows range intervals tuning and sampling the received signals with a constant rate. By this, it is particularly attractive for portable applications. Finally, the system performance has been tested in a traffic surveillance experiment.

Interferometric ISAR Imaging on Maritime Target Applications: Simulation of Realistic Targets and Dynamics

Abstract—ISAR imaging of maritime targets has greater success than other ISAR applications due to the constant oscillatory motions induced by waves and wind. However, relative target motions are usually unknown, difficult focusing, image interpretation and target classification. Using interferometry to obtain the height information makes possible to obtain a 3-D reconstruction of a target, aiding image focusing, image interpretation and target classification. However, the information and utility of the ISAR image and the interferometric information depends highly on geometry and targets dynamics. In this paper we will study the influence of movement dynamics in interferometric ISAR imaging using a realistic extended moving target simulation, a general geometry and complex dynamics models.

Experimental Performance Comparison of Six-Port and Conventional Zero-IF/Low-IF Receivers for Software Defined Radio

This paper presents an experimental performance comparison among three RF architectures that are very suitable for Software Defined Radio (SDR) implementation: zero-IF, low-IF, and six-port network. A six-port receiver and a dual zero-IF/low-IF receiver have been developed for this purpose. Six-port receiver is a very promising and flexible RF architecture for the low-cost implementation of integrated microwave and millimeter-wave systems. Competitive advantages such as ultra-broadband behavior, low-cost, reconfigurability, and low power consumption, point to the six-port architecture as a good candidate to implement a SDR. However, two issues on broadband six-port receivers require intensive research: dynamic range extension, and miniaturization. In this paper, two solutions are proposed to solve these problems: the use of biased detector diodes for dynamic range extension, and the use of low temperature co-fired ceramic (LTCC) technology for six-port reduction. The measurement results indicate that the six-port receiver shows high potential benefits and advantages compared to conventional zero-IF and low-IF receivers. In addition, the capability of the six-port architecture to operate as both zero-IF and low-IF receivers has been experimentally demonstrated for the first time.

Vehicular Traffic Surveillance and Road Lane Detection Using Radar Interferometry

Speed enforcement on public roadways is an important issue in order to guarantee road security and to reduce the number and seriousness of traffic accidents. Traditionally, this task has been partially solved using radar and/or laser technologies and, more recently, using video-camera based systems. All these systems have significant shortcomings that have yet to be overcome. The main drawback of classical Doppler radar technology is that the velocity measurement fails when several vehicles are in the radars beam. Modern radar systems are able to measure speed and range between vehicle and radar. However, this is not enough to discriminate the lane where the vehicle is driving on. The limitation of several vehicles in the beam is overcome using laser technology. However, laser systems have another important limitation: They cannot measure the speed of several vehicles simultaneously. Novel video-camera systems, based on license plate identification, solve the previous drawbacks, but they have the problem that they can only measure average speed but never top-speed. This paper studies the feasibility of using an interferometric linear frequency modulated continuous wave radar to improve top-speed enforcement on roadways. Two different systems based on down-the-road and across-the-road radar configurations are presented. The main advantage of the proposed solutions is they can simultaneously measure speed, range, and lane of several vehicles, allowing the univocal identification of the offenders. A detailed analysis about the operation and accuracy of these solutions is reported. In addition, the feasibility of the proposed techniques has been demonstrated with simulations and real experiments using a Ka-band interferometric radar developed by our research group.

Software Defined Radio technologies for emergency and professional wide band communications

In this paper several RF architectures have been investigated in order to find a flexible, reconfigurable and multi-mode RF front-end for Software Defined Radio (SDR). The objective is to develop a new professional mobile broadband communication system, oriented to Public and Governmental Services. Different receiver prototypes based on the studied architectures have been implemented. The comparison of the RF architectures from the measurement results will be presented. The receiver prototypes have been validated for different types of modulation and data rates.

MINIATURIZED 0.3{6 GHz LTCC SIX-PORT RECEIVER FOR SOFTWARE DEFINED RADIO

The six-port architecture reemerges from the search of low-cost, multi-band and multi-standard transceivers. Its inherent advantages, especially its broadband behavior, make this a structure a good candidate to implement a Software Deflned Radio (SDR). However, broadband six-port network designs lead to large size circuits, especially for operating frequencies in the lower gigahertz region. New technologies must be explored in order to achieve compact size and low-cost productions for conflgurable radio terminals and mobile communication applications. In this paper, the Low Temperature Co-flred Ceramic (LTCC) technology is proposed for implementing a broadband six-port receiver. A compact (30mm £ 30mm £ 1:25mm) four-octave LTCC six-port receiver is presented. Experimental demodulation results show a good performance over the frequency range from 0.3 to 6GHz. The demodulation of up to 15.625Msymbol/s signals, i.e., 93.6Mbps for 64-QAM, has been satisfactorily performed, with a measured Error Vector Magnitude (EVM) value of 3.7%.