  Omnidirectional path loss models are vital for radiosystem design in wireless
communication systems, as they allow engineers to perform network simulations
for systems with arbitrary antenna patterns. At millimeter-wave frequencies,
channel measurements are frequently conducted using steerable highgain
directional antennas at both the transmitter and receiver to make up for the
significant increase in free space path loss at these frequencies compared to
traditional cellular systems that operate at lower frequencies. The
omnidirectional antenna pattern, and resulting omnidirectional received power
must therefore be synthesized from many unique pointing angles, where the
transmit and receive antennas are rotated over many different azimuth and
elevation planes. In this paper, the equivalent omnidirectional antenna pattern
and omnidirectional received power are synthesized by summing the received
powers from all measured unique pointing angles obtained at antenna halfpower
beamwidth step increments in the azimuth and elevation planes, and this method
is validated by demonstrating that the synthesized omnidirectional received
power and path loss are independent of antenna beamwidth, through theoretical
analyses and millimeter-wave propagation measurements using antennas with
different beamwidths. The method in this paper is shown to provide accurate
results while enhancing the measurement range substantially through the use of
directional antennas.
