2. B. F. Wang and Y. T. Lo, “Microstrip Antennas for Dual- Frequency Operation,” IEEE Trans. Antennas Propagat., Vol.

3. Y. T. Lo, C. E. Slupien, and S. S. Zhong, “A Study of Mxrostrip Antennas for Multiple Band Operation,” RADC Final Report No. RADC-TR-82236, 1982.

4. A. K. Bhattacharyya and R. Garg, “Input Impedance of Annular

AP-32. 1984, pp. 938-943.

A

A. Das, S. K. Das, and S. P. Mathur, “Radiation Characteristics of Higher Order Modes in Microstrip Ring Antenna,” IEE Proc., Pr. H , Vol. 131, 1984, pp. 102-106.

Received 9-23-88

crowave and Optical Technolow Letters, 1 /lo, 389-392 Ring Microstrip Antenna Using Circuit Theory Approach,” IEEE Truns. Antennus Propagat., Vol. AP-33, 1985, pp. 369-373.

0 1988 John Wiley & Sons, Inc. CCC 0895-2477/88/$4.00

ERRATUM

TRANSMISSION METHOD FOR

OPTICAL SYSTEMS Microwave and Optical Technology Letters Vol. 7, No. 5, July 1988, pp. 161 - 163

A PHASE-NOISE-COMPENSATING

PHASE-MODULATED COHERENT

S. Betti, F. Curti, G. De Marchis, and E. lannone Fondazione Ugo Bordoni Viale Europa 190-001 44 Rorna Italy

Equation (1) should be written as

s ( t > = (XA, + yA,)exp[ - ; ( q t + + ( t > + m ( t > ) ]

+ ( x A , - y&)exp[ -;(u2t + + ( t > + P ) I (1)

and Equation (4) as

Moreover, the second line after Equation (1) should be read as “2A2 = 2(IA,I2 + lA,1*) is proportional to the received opti- cal power. . . .”

Received 9-15-88

Microwave and Optical Technology Letters, 1/10, 392 0 1988 John Wiley & Sons, Inc. CCC 0895-2477/88/$4.00

392 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 1, No. 10, December 1988