Planar retrodirective array reflector using dual-slot antennas

Abstract

clear that the intrinsic resonance frequency fi is not changed by using any of the slot types. Fig. 4 shows the measured H-plane (x z plane) radiation patterns with the dumb-bell slot at fi = 1.49GHz andf, = 1.94GHz, respectively. fi is the matching resonance frequency of the rectangular patch with the dumb-bell slot on the ground plane. fi is the intrinsic resonance frequency of the rectangular patch without the dumb-bell slot on the ground plane, which was almost the same as the calculated resonance frequency 1.9GHz. These frequencies are used for PDC and PHS cell phone systems in Japan. 8 = 0" and fl = f180" is the z-direction, which is perpendicular to the rectangular patches. From these results, an almost omnidirectional radiation pattern with 5 dB gain variation was obtained at f i , and a bidirectional radiation pattern was obtained at fi. Therefore, the proposed microstrip antenna can realise an omnidirectional radiation pattern or a bidirectional radiation pattern simultaneously.

Retro‐directive array using two‐port dual polarized elements

“…Here, C pg , C pd , L g , L s , L d , R g , R s , and R d represent the eight external parasitic-pad effects, and the 10 elements: C gs , C gd , C ds , R j , R fd , R i , R fs , R ds , G mo and correspond to the intrinsic transistor. It is important to mention that in [1,2] the intrinsic transistor is modeled by seven elements only, while the extended circuit model proposed in [3] and shown in Figure 1, includes three additional elements (R j , R fd , R fs ). In this model, R j is added to C gd to make the circuit symmetrical in reference with drain and source.…”

“…In [1,[4][5][6][7][8][9][10], different methods to remove the parasitic-pad effects in FET's and HBT's were proposed. Some methods using open/short test structures were presented in [6] and [10], while others based on forward and reverse bias measurements are given in [1][2][3]11].…”

“…In [2], a seven-element model and exact equations were proposed. However, for the extended model given in Figure 1, the differential resistances R fs and R fd are extracted neglecting the frequency effect on Y-parameters, requiring measurements at very low frequencies [3]. On another work [8], a long procedure based on approximations and an iterative method was proposed.…”

“…In early years, dipole or horn antennas were used to implement the array reflector and coaxial cables were chosen to connect the antennas [1,2]. Recently, planar antennas and printed transmission lines have been proposed to implement passive arrays [3][4][5][6]. Both 1D and 2D arrays have been treated.…”

Σχεδίαση Κατασκευή Και Μετρήσεις Στοιχείων Για Επανακατευθυντικά Συστήματα

“…Η απόκλιση αυτή οφείλεται στο διάγραμμα ακτινοβολίας του στοιχείου της στοιχειοκεραίας [5,1997]. Σε άλλη πρόταση [6,1997], [7,1998] οι γραμμικές πολώσεις των κεραιών σε κάθε ζεύγος ήταν κάθετες μεταξύ τους ενώ επιλέχθηκαν κεραίες [6,1997], [8,1998], [9,1998] Μελετήθηκε επίσης η περίπτωση της ταυτόχρονης πρόσπτωσης κυμάτων από διαφορετικές διευθύνσεις και σε διαφορετικές συχνότητες [11,1999] και το πώς επηρεάζεται το διάγραμμα ακτινοβολίας της επανακατευθυντικής κεραίας σε αυτή την περίπτωση. Σε αυτή την περίπτωση η επανακατευθυντική στοιχειοκεραία παρουσιάζει τη δυνατότητα επανακατεύθυνσης σε κάθε συχνότητα ξεχωριστά.…”