Next-generation wireless networks, such as 5G networks, will use millimeter waves (mmWaves) operating at 28 GHz, 38 GHz, 60 GHz, or higher frequencies to deliver unprecedentedly high data rates, e.g., 10 gigabits per second. Due to high attenuation at this higher frequency, use of directional antennas is commonly suggested for mmWave communication. It is therefore important to study how different antenna configurations at the transmitter and receiver effect received power and data throughput. In this paper, we describe field experiments with mmWave antennas for indoor multipath environments and report measurement results on a multitude of antenna configurations. Specifically, we examine four different mmWave systems, operating at two different frequencies (38 and 60 GHz), using a number of different antennas (horn antennas, omnidirectional antennas, and phase arrays). For each system, we systematically collect performance measurements (e.g., received power), and use these to examine the effects of beam misalignment on signal quality, the presence of multipath effects, and susceptibility to blockage. We capture interesting phenomena, including a multipath scenario in which a single receiver antenna can receive two copies of signals transmitted from the same transmitter antenna over multiple paths. From these field experiments, we discuss lessons learned and draw several conclusions, and their applicability to the design of future mmWave networks.