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In this paper, a novel compact microstrip patch antenna with a boresight filtering gain response is proposed. The proposed antenna consists of a radiating patch, a ground plane, two pairs of slots respectively etched on the radiating patch and the ground plane, two shorted vias connecting the radiating patch and the ground plane. The slots on the ground plane not only provide a gain null in the lower transition band, but also introduce a new low‐resistance resonance which is beneficial to widen the impedance bandwidth. The slots on the radiating patch provide another gain null in the upper transition band. The two shorted vias are used to further adjust the reflection coefficient and the gain performance of the antenna. Since no extra circuits are introduced, the proposed antenna is compact. A prototype operating at 3.0 GHz was fabricated and measured. It demonstrates that the proposed antenna has a bandwidth of 3.5% and a gain of 6.0 dBi in a profile of 0.015 λ0. At the same time, a good filtering gain response is realized. [ABSTRACT FROM AUTHOR]

An ultra‐wideband pulse crossover with a reversed polarity channel is proposed, and a time‐domain analysis is utilized to design the crossover and estimate its performance. Two crossed channels are designed based on post‐wall slotline (PWS) and conventional slotline, and one of the two channels provides an output with reversed polarity. At the overlapping region, the PWS degrades to slotline on single layer to improve isolation between channels. Normalized Euclid distance of short pulses is utilized to evaluate the isolating and polarity reversing features of the crossover, and the matrices of normalized Euclid distance are then obtained and applied to the design procedure. The proposed crossover are modeled and fabricated for simulation and measurement, and the simulated and measured results agree well. Minimum of return loss and isolation is more than 12 dB within an ultra‐wide bandwidth from DC to 8.5 GHz. Moreover, in time domain, the proposed crossover shows good performance in pulse transmission, including high fidelity and amplitude ratio of input and output signals. The characteristics of the crossover indicate the practicability in short pulse application, and rectangular pulse transmission performance is evaluated to verify the ability. [ABSTRACT FROM AUTHOR]

A measurement method of an active element antenna pattern in a hybrid antenna array with heterodyne architecture under a real environment is proposed and applied to the design of an ultralow sidelobe level scanning array. To avoid the phase uncertainty caused by the local oscillator signal in the heterodyne architecture, a phase‐normalized active element pattern (PNAEP) is used to characterize the element antenna patterns of both amplitude and phase. The PNAEP has almost taken account of all the practical factors of an array, such as mutual couplings, various types of element antennas, unequal spacing, or diverse environmental effects. The PNAEP is measured with a 16‐element scanning receiving array with a heterodyne architecture to validate the feasibility of the PNAEP. Based on the PNAEP, the scanning array achieve an ultralow sidelobe level of −33 dB. Applying to various receiving array architectures the PNAEP method is a feasible and universal tool for array synthesis and optimization under real environments. [ABSTRACT FROM AUTHOR]

An exponential tapered post‐wall slotline antenna loaded with dielectric lens is proposed and demonstrated. The theoretical profile of the loaded dielectric lens is derived, and its physical explanation is presented. Besides, the proposed post‐wall structure in the antenna ensures low available characteristic impedance as well as low cross‐polarization levels of the antenna. The proposed antenna exhibits an 18.12 GHz impedance bandwidth between 1.88 and 20 GHz and a peak gain of 10.9 dBi. The measured E‐plane and H‐plane cross‐polarization level is −37.0 and − 26.0 dB in boresight direction, respectively. Compared to the antenna without dielectric lens, the average gain of the proposed antenna increases by 3 dB from 14 to 20 GHz, and the pulse peak‐peak gain increases by 1.59 dB, and the tailing signal levels is about 0.35 dB lower. [ABSTRACT FROM AUTHOR]