A wideband and high-gain planar endfire antenna based on spoof surface plasmon polaritons (SSPPs) at millimeter-wave (MMW) band is presented. First, a unilaterally corrugated surface antenna is demonstrated to radiate endfire beam tilted up from the flat plane of the corrugated metal teeth due to the effect of finite ground plane. Then, a SSPPs endfire antenna is designed with two symmetrically corrugated surfaces on the double sides of a metal strip. To excite the desired beam, the feeding network is comprised of a power divider and two L-shaped slots, so as to simultaneously produce oppositely tangential electric fields and identically normal electric fields. Moreover, the two equivalent identically tangential magnetic current sources above the corrugated surfaces are excited by flared feeding slot transitions. As a result, a synthetic endfire beam with zero-tilted angle is achieved. In final, such an antenna, operating in a range from 30 to 50 GHz with 50% fractional bandwidth, is designed with maximum gain of 16 dBi, as well confirmed in the experiment. The proposed SSPPs endfire antenna holds a very low profile and it is promising for application in MMW communication systems.

This communication presents a wideband endfire antenna based on odd mode spoof surface plasmon polaritons (SSPPs). The odd mode SSPPs is supported by dipole-shaped unit cells. Since the introduction of phase reversal crossover, the ordinary antenna is segment to two sections of SSPPs with half-length that make up a two-element array. The endfire directivity of the proposed modified SSPPs antenna is enhanced due to the extra phase added by the phase reversal crossover. It achieves 67% relative bandwidth from 4 to 8 GHz. The maximum measured endfire gain attains 7.9 dBi. The simulated and measured results are in good agreement over the operating band. The proposed antenna is wideband, low-profile, small aperture, and low-cost.

In this paper, a Schottky diode detector based on spoof surface plasmon polariton (SPP) structure is reported. The detector consists of an input matching network, a Schottky diode, and an output filtering network. The proposed detector is designed using a step impedance section and λ/4 radial stub integrated in the circuit. Compared with the conventional microwave detector, experimental results show that the proposed detector achieves 31% improvement of detection sensitivity with the high input radio frequency (RF) power and 95% improvement of the detection sensitivity with the low input RF power by the SPPs. The proposed detector is attractive for use in aircraft, vehicles, and wireless communication due to its miniaturization, low-cost, and easy fabrication with planar circuits.

In this paper, we propose a half-mode substrate integrated waveguide (HMSIW) leaky wave antenna (LWA) based on composite right/left handed (CRLH) transimission line (TL). The unit cell of the proposed antenna consists of two vertical slots on the microstrip and two metal vias. The equivalent series capacitance and the equivalent shunt inductance in the CRLH structure are realized by vertical slots and two vias, respectively. We simulated the unit cell and the proposed antenna. The antenna can achieve continuously wide beam scanning from backward to forward. The beam scanning angles from −50 degrees to 30 degrees.