Restriction of communication area is preferable in view point of security. In this paper, a communication area restriction method is proposed. In the proposed method, binomial coefficient array for transmitting and for jamming is used. In the conventional method, the beam for jamming was formed using 2 elements; while in this paper, the beam is formed using 8 elements binomial array. As a result of analysis, it is shown that the undesired radiation is drastically reduced by the proposed method.