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Block diagram of monostatic radar using circulator.
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Os mísseis de cruzeiro são armamentos de uso tático e poucos países possuem essa tecnologia. O seu uso vem sendo crescente no decorrer dos anos e desenvolver uma forma de detectá-lo é importante para capacitar um sistema anti-aéreo de defesa. Esse trabalho propõe realizar a predição radar do míssil de cruzeiro Tomahawk baseado na RCS dinâmica na fr...
Citations
... The authors used a balanced feed antenna and the loss was reduced to 0.75 dB in both the transmitter and receiver paths. In [11], two circulators were used with a two-layer out-of-phase power divider to achieve 40 dB isolation over about 32% FBW with 4 dB loss in both the transmitter and receiver at 3.2 GHz centre frequency. In [12], a balun-based canceller was introduced, utilising two circulators with a balun to achieve 40 dB isolation from 2 to 4 GHz with 67% FBW. ...
Abstract A study and analysis of an X‐band transceiver self‐interference cancelation system based on wideband 90° phase‐shifters are presented. The analysis introduces the conditions for perfect isolation and imbalance mitigation in the system. A high isolation, low path‐loss transmitter leakage canceller for single antenna frequency‐modulated continuous wave radar applications is developed and fabricated to validate the provided analysis. The canceller consists of two circulators, three Wilkinson combiners/dividers and three phase‐shifters. Practically, similar circulators have certain performance mismatches, which degrades conventional canceller performance. The proposed system uses a 90° phase‐shifter along with the Wilkinson to allow the tuning of the phase difference for each branch to compensate for circulators' mismatches. The proposed canceller is designed at a 10 GHz centre frequency. The measurement results show more than 40 dB isolation for 600 MHz bandwidth (9.6–10.2 GHz) with less than 1.7 and 1.4 dB transmitter and receiver path‐losses, respectively. The good agreement between measurements and simulations verifies the proposed system as well as the proposed analysis.
... Thus, from Equations (1.12) and (1.14) it can be said that this topology can also achieve, theoretically, infinite isolation between the transmit and receive ports by eliminating the signals leaked from the circulators and the signals reflected from the antennas, only if it is assumed that the circulators have identical performances or S-parameters, and if both mismatches between the antenna and the two circulators are also identical. This technique was presented in [72][73][74]. ...
La technologie In-Band Full-Duplex a pour objectif d’augmenter l’efficacité spectrale des liaisons sans-fils en permettant à deux systèmes de communiquer simultanément dans la même bande de fréquence. Dans cette configuration In-Band Full-Duplex, le principal défi consiste à annuler ou réduire les signaux d’auto-interférence, qui se couplent de l’émetteur vers son propre récepteur. Divers circuits d’annulation d’auto- interférence peuvent alors être mis en œuvre : au niveau de l’antenne, de l’étage analogique et/ou numérique. Les techniques classiques d’annulation d’auto-interférence sont majoritairement dédiées aux systèmes à bande étroite et peu de travaux ont été menés pour étendre leurs performances à un fonctionnement en large-bande et encore moins en Ultra-Large-Bande. Dans ce travail, nous nous focalisons sur l’étude des techniques d’annulation compatibles avec un fonctionnement Ultra-Large-Bande et sur leurs mises en œuvre. Les systèmes antennaires proposés sont basés sur une technique d’annulation en champ proche qui utilise quatre antennes et deux baluns. Les avantages des systèmes développés sont multiples, ils proposent tous une bande passante extrêmement large tout en maintenant un niveau d’annulation d’auto-interférence au moins supérieur à 55-60 dB sur cette bande avec des configurations permettant soit d’en augmenter la solidité mécanique, soit d’obtenir unedouble polarisation ou encore avec une alimentation innovante des antennes.
... Thus, from Equations (1.12) and (1.14) it can be said that this topology can also achieve, theoretically, infinite isolation between the transmit and receive ports by eliminating the signals leaked from the circulators and the signals reflected from the antennas, only if it is assumed that the circulators have identical performances or S-parameters, and if both mismatches between the antenna and the two circulators are also identical. This technique was presented in [72][73][74]. ...
In-band full-duplex technology aims to mitigate the scarcity of spectral resources by allowing two radios to communicate simultaneously in the same frequency band. The main challenge for full-duplex radios is to cancel the self-interference signals, which couple from the transmitter of one radio to its own receiver, by implementing various self-interference cancellation circuitry at the antenna, analog, and digital stages of the radio front-end. Conventional self-interference cancellation techniques were dedicated for narrowband systems and little work has been conducted to extend their performance for wideband operation. Thus, in this work, we focus on studying the wideband potential of the available cancellation techniques and implementing wideband full-duplex systems based on those techniques. The implemented systems are based on the near-field cancellation technique which uses four antennas and two baluns. The systems' merits vary from extremely wide bandwidth to higher mechanical solidity and dual-polarization, but they all can maintain a decent amount of cancellation.
