A UWB Antenna Array Integrated with Multimode Resonator Bandpass Filter

• Published in: Electronics (Basel) 2021-03, Vol.10 (5), p.607
• Main Authors: Ahmed, Sharif, Kim Geok, Tan, Alias, Mohamad Yusoff, Hossain, Ferdous, Alsariera, Hussein, Abdaziz, Azlan, Soh, Ping Jack
• Format: Article
• Language: English
• Subjects: Antenna arrays; Antenna design; Antennas; Bandpass filters; Bandwidths; Computer simulation; Design; Design modifications; Frequency ranges; Ground plane; Internet of Things; Multimode resonators; Mutual coupling; Radar equipment; Radar tracking; Reflectance; Software; Spectrum allocation; Ultrawideband; Ultrawideband radar; Unmanned aerial vehicles; Wireless communications
• ISSN: 2079-9292; 2079-9292
• DOI: 10.3390/electronics10050607

This paper presents a novel design of a modified ultrawideband (UWB) antenna array integrated with a multimode resonator bandpass filter. First, a single UWB antenna is modified and studied, using a P-shape radiated patch instead of a full elliptical patch, for wide impedance bandwidth and high realized gain. Then, a two-element UWB antenna array is developed based on this modified UWB antenna with an inter-element spacing of 0.35 λL, in which λL is the free space wavelength at the lower UWB band edge of 3.1 GHz, compared to 0.27 λL of a reference UWB antenna array designed using a traditional elliptical patch shape. The partial ground plane is designed with a trapezoidal angle to enhance matching throughout the UWB frequency range. The mutual coupling reduction of a modified UWB antenna array enhances the reflection coefficient, bandwidth, and realized gain, maintaining the same size of 1.08 λ0 × 1.08 λ0 × 0.035 λ0 at 6.5 GHz center frequency as that of the reference UWB antenna array. The UWB antenna array performance is investigated at different inter-element spacing distances between the radiated elements. To add filtering capability to the UWB antenna array and eliminate interference from the out-of-band frequencies, a multimode resonator (MMR) bandpass filter (BPF) is incorporated in the feedline while maintaining a compact size. The measurement results showed a close agreement with simulated results. The proposed UWB filtering antenna array design achieved a wide fractional bandwidth of more than 109.87%, a high realized gain of more than 7.4 dBi, and a compact size of 1.08 λ0 × 1.08 λ0 × 0.035 λ0 at 6.5 GHz center frequency. These advantages make the proposed antenna suitable for UWB applications such as indoor tracking, radar systems and positioning applications.