[1] U New Mexico, ECE Dept, Albuquerque, NM 87131 USA
[2] K&A Wireless, Albuquerque, NM 87106 USA
[3] U New Mexico, FITE Dept, Albuquerque, NM 87131 USA
[4] Innofone, Santa Monica, CA 90401 USA
[5] Pontificia Univ Catolica Rio Grande do Sul, Porto Alegre, RS, Brazil