In this paper, A Vector Modulator based a wideband analog phase shifter is realized with four P-I-N diode attenuators, an asymmetric coupled line coupler, a symmetric coupled line coupler, and a power combiner. Simple configuration to have advantages in cost, size, power, and the number of passive circuits is presented. The phase variation due to phase and amplitude error of a P-I-N diode attenuator is derived and used to optimize the overall circuit. The phase shifter shows a total phase shift of 360$^{circ}$, a 8.2$^{circ}$maximum phase error, and a 16${pm}$2.5 dB insertion loss over the wide frequency range of 1 GHz to 3 GHz.