A compact proximity‐fed 2.4 GHz monostatic antenna with wide‐band SIC characteristics for in‐band full duplex applications

Shoaib

International Journal of Antennas and Propagation

et al. 2021

Self Cite

This paper presents a compact, dual polarized bistatic (two closely spaced transmit and receive radiators) patch antenna with excellent interport isolation performance. The presented antenna system employs differential receive mode operation for the cancellation of self-interference (SI) to achieve very high interport isolation for 2.4 GHz in-band full duplex (IBFD) applications. The presented antenna is based on two closely spaced radiators and a simple 3 dB/180° coupler for differentially excited receive mode operation. The 3 dB/180° coupler performs as a passive self-interference cancellation (SIC) circuit for the presented antenna. The small form-factor structure is realized through via interconnections between the receiving patch and SIC circuit. The prototype of the presented antenna characterizes better than 105 dB peak interport isolation. Moreover, the recorded interport isolation is more than 90 dB and 95 dB within 60 MHz and 40 MHz bandwidths, respectively. The measured gain and cross-polarization levels reflect superior radiation performance for the validation model of the proposed antenna. The presented antenna offers DC interport isolation too, which is required for active antenna applications. The novelty of this work is a compact (small form-factor) antenna structure with very high peak interport isolation along with wider SIC bandwidth as compared to previously reported antennas for full duplex applications.

Section: Introductionmentioning

confidence: 99%

A Compact, Bistatic Antenna System with Very High Interport Isolation for 2.4 GHz In-Band Full Duplex Applications

Shoaib

International Journal of Antennas and Propagation

et al. 2021

Self Cite

“…[19][20][21] The polarization diversity for dual polarized proximity-fed antennas can achieve adequate levels of isolation over the shared impedance bandwidth of both T x and R x ports. [19][20][21] The additional isolation can be achieved through analog/RF domain SIC topologies like single or multiple-taps, which sample the signals from T x port and subtract these processed signals from R x port. 8,[22][23][24][25][26] Inherently, the single-tap SIC topology achieves narrow band isolation due to stringent signal inversion requirements.…”

Section: Introductionmentioning

confidence: 99%

“…The patch antennas provide very narrow impedance bandwidth due to their resonating nature. The proximity feeding is one technique to achieve improved impedance bandwidth for patch antennas 19‐21 . The polarization diversity for dual polarized proximity‐fed antennas can achieve adequate levels of isolation over the shared impedance bandwidth of both T x and R x ports 19‐21 .…”

Section: Introductionmentioning

confidence: 99%

“…The proximity feeding is one technique to achieve improved impedance bandwidth for patch antennas 19‐21 . The polarization diversity for dual polarized proximity‐fed antennas can achieve adequate levels of isolation over the shared impedance bandwidth of both T x and R x ports 19‐21 . The additional isolation can be achieved through analog/RF domain SIC topologies like single or multiple‐taps, which sample the signals from T x port and subtract these processed signals from R x port 8,22‐26 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High isolation, proximity‐fed monostatic patch antennas with integrated self‐interference cancellation‐taps for ISM band full duplex applications

Int J RF Microw Comput Aided Eng

Chaudhry

2020

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This work presents two dual polarized proximity-fed monostatic patch antennas with improved interport isolation for 2.4 GHz industrial, scientific and medical band same frequency full duplex wireless applications. The presented antennas achieves the high interport decoupling through intrinsic isolation of the polarization diversity in conjunction with a simple single-tap and two-taps self-interference cancellation (SIC) topologies. The polarization diversity isolation is achieved through two perpendicular microstrip feeds for proximity feeding to excite orthogonal polarization mode for transmit (T x) and receive (R x) modes. The prototype for proposed antenna with integrated single-tap and two-taps SIC circuit is tested to record its interport isolation, impedance bandwidths and gains for both T x and R x ports. The implemented antenna with single-tap SIC circuit demonstrates 10 dB return-loss bandwidth of ≥100 MHz for both T x and R x ports. The measured isolation exceeds 40 dB over the 40 MHz bandwidth. Moreover, the recorded peak isolation is better than 74 dB for implemented antenna prototype. Furthermore, the 40 MHz bandwidth with 40 dB isolation can be tuned with the help of SIC-tap as demonstrated through the experimental results. The measured gain levels are around 4.6 dBi for both T x and R x port. The same antenna structure with integrated two-taps SIC topology features better than 55 dB isolation within 10 dB return loss bandwidth of 100 MHz. The peak isolation exceeds 97 dB and isolation levels are better than 60 and 80 dB over 50 and 20 MHz bandwidths, respectively, for presented antenna with two-taps SIC configuration. The compact antenna offers comparatively wider impedance and isolation bandwidth with improved SIC levels compared to previous designs.

“…The differential feeding is a very useful SIC technique to achieve high T x – R x isolation without degrading the radiation performance of monostatic antennas. The differential feeding can be used either at T x / R x or simultaneously at both ports [18–21]. The achievable SIC performance of differentially driven antennas is dependent upon the antennas symmetry and the response of the employed differential circuit.…”

Section: Introductionmentioning

confidence: 99%

A compact, dual-polarized patch antenna with improved T_x–R_x isolation for 2.4 GHz single frequency full-duplex applications

Basit

Int. J. Microw. Wireless Technol.

2020

Self Cite

A compact dual-polarized monostatic antenna (single radiator for transmit and receive modes) is presented with differential receive mode operation to achieve excellent interport isolation for 2.4 GHz single frequency full-duplex or in-band full-duplex applications. The presented antenna comprises three ports radiating element (patch) and a simple 3 dB/180o ring hybrid coupler has been utilized for differentially excited receive mode operation. The 3 dB/180o ring hybrid coupler acts as a self-interference cancellation (SIC) circuit for effective suppression of RF leakage from the transmit port to provide very high interport decoupling between transmit and receive ports. A compact antenna structure has been realized by using two-layered printed circuit board through vias interconnections of both receive ports of the antenna with inputs of SIC circuit. The validation model of proposed antenna offers more than 95 dB peak interport isolation. Moreover, the experimentally measured interport isolation is better than 70 dB throughout the antenna's 10 dB return-loss impedance bandwidth (BW) of 50 MHz (2.38–2.43 GHz). Furthermore, the recorded isolation is more than 80 dB in 20 MHz BW. The implemented antenna has good radiation characteristics including nice gain and low cross-polarization levels as endorsed by measurements. Same antenna structure with microstrip-T feeds can provide DC isolated ports with same interport RF isolation performance for active antenna applications. Such antenna with DC interport isolation will avoid the requirements of additional series capacitors on transmit and receive ports of antenna.